How to use a scan tool?

Read the Car Code(s)

  1. Turn on the diagnostic tool. Basic tools should have a simple power button somewhere on the unit.
  2. Access the diagnostic scanner. Some scanners will automatically start to read the car codes once powered on.
  3. Record the data.
  4. Optional: Clear the codes.

What can be checked with a scan tool?

Your scan tool can run Functional Tests that fall into four categories. 1) Information tests, 2) Toggle tests, 3) Variable Control tests, and 4) Reset tests. Information tests provide information such as the VIN number and the Calibration Part Number.

What is the difference between OBD and OBD2?

1. OBD1 is connected to the console of a car, while OBD2 is remotely connected to the vehicle. 2. OBD1 was used during the earlier years of the car manufacturing industry, while OBD2 was only introduced in car models produced in the early 1990’s.

What is the difference between a scan tool and a code reader?

A code reader is a simplified version of a scan tool, but it’s only capable of performing basic scans of trouble codes. A scan tool can read and clear trouble codes, and it may also provide advanced data reading and playback features, knowledge bases, diagnostic procedures, and built-in testing equipment.

What is the purpose of scan tool?

Scan tools provide vehicle data and trouble codes stored within the vehicle computer networks. Access to these codes and data direct the technician to the area of concern or where/what a malfunction could be.

Can you scan a car with no check engine light?

In short, yes; it’s possible to diagnose a problem with a vehicle even if the check engine light does not illuminate.

Can you damage your car using an OBD2 Scanner?

Apart from some “killer commands”, the ECU might have been destroyed electrically. The OBDII-Interface can implement several different data buses with different voltage levels. If the bus lines get connected to +12V, this could destroy something.

Does my car have OBD1 or OBD2?

All cars and light trucks built and sold in the United States after January 1, 1996 were required to be OBD II equipped. In general, this means all 1996 model year cars and light trucks are compliant, even if built in late 1995. 2) There will be a note on a sticker or nameplate under the hood: “OBD II compliant”.

Are OBD scanners worth it?

No it is not worth the cost. If you live in the states almost all major auto parts chains (Advance Auto, Autozone, etc) will do a check or even loan you the tool for free. Unless you’re checking codes daily, it may be cost prohibitive. The error codes produced by OBD2 are rather generic.

Which OBD scanner is best?

#1 Best Overall: Launch CRP129E Scan Tool. #2 Best Bluetooth Scanner: BlueDriver Bluetooth Pro OBDII Scan Tool. #3 Best Budget Scanner: Foxwell NT301 OBD2 Scanner. #4 Autel MaxiCOM MK808 Scanner.

How To Use An OBD2 Scanner (Step-By-Step Guide + 3 FAQs)

An OBD2 scanner can assist you or your technician in determining whether or not your vehicle is in excellent working order. In automotive diagnostics, an OBD2 scanner is a diagnostic instrument that communicates with your vehicle using the Diagnostic Link Connector. A wired connection, Bluetooth, or WiFi are all used to accomplish this task, which allows you to scan every diagnostic issue code generated by your vehicle’s computer. The challenge is, however, how to make use of an OBD2 scanner.

We’ll also address some frequently asked questions (FAQs) to help you gain a better grasp of this product.

This Article Contains:

  • What Is the Best Way to Use an OBD2 Scanner? (Step-By-Step)
  • 3 Frequently Asked Questions About Using an OBD2 Scanner
  • In what ways are OBD1 scanners and OBD2 scanners distinct from one another? What are the many types of OBD II scanners available? What Factors Should You Take into Account When Purchasing An OBD2 Scanner

Let’s get this party started.

How To Use AnOBD2 Scanner? (Step-By-Step)

The process of using an OBD2 automobile diagnostic scanner is basic and uncomplicated. Here’s a straightforward step-by-step procedure:

  • Step 1: Locate the Diagnostic Link Connector on your computer. To use the DLC, connect your OBD2 code reader or scanner to the DLC. To use the scanner, enter the information that is requested on the screen of the scanner. Step 4: Access the OBD Code Scanner Menu
  • Step 5: Identify and understand the OBD Codes
  • Step 6: Restart the vehicle. Step 6: Proceed to the Trouble Code Diagnosis stage. Step 7: Reset the Check Engine Light (if it is illuminated).

Step 1: Locate The Diagnostic Link Connector

If your vehicle was built after 1996, it is equipped with a Diagnostic Link Connector (DLC), sometimes known as an OBD2 port. There are 16 pins on the left side of the driver’s dashboard, behind the steering column, and it is normally hidden behind a door or flap to prevent accidental connection. If you are unable to locate the OBD2 port, you may always consult your vehicle’s owner’s handbook.

Step 2: Connect Your OBD2 Code Reader Or Scanner To The DLC

Make sure your vehicle is switched off once you have located the DLC. Using an OBD2 connection cable, connect the end of the OBD2 scan tool to the Diagnostic Link Connector on the vehicle. If you have a Bluetooth OBD2 scanner, you may just plug the scanner into the OBD II port without any further steps. Check the scanner instructions to see whether you need to maintain the car in ONoridle mode after connecting to the DLC, and if so, follow those instructions. This step is critical since using the incorrect way might cause damage to the scan tool application.

Check for a message on your OBD II scanner to confirm that the connection to your OBD2 system has been established.

Step 3: Enter The Information Requested On The Scanner Screen

Your automobile is equipped with a VIN (Vehicle Identification Number) (VIN). Before your scanner can generate any OBD2 codes, you may be required to provide the vehicle identification number (VIN). Other information, such as your engine and vehicle model, may be requested by the code scanner. What is the VIN number and where can you locate it? If the scanner asks for it, the VIN may be found on a sticker that is generally located in the bottom right-hand corner of the windshield on the driver’s side.

Step 4: Access The Scanner Menu For OBD Codes

Now, navigate to the code scanner menu screen, where you may select from a variety of various automobile systems. Select a system that will allow the scanner to display every active and pending code. What’s the difference between the two? An active code causes the check engine light to illuminate, but a pending code indicates that the emission control system is malfunctioning. Please bear in mind that if the same problem continues to recur, the pending code might become an active code.

Please keep in mind that the display on your auto code reader or scanner will differ based on the type of scanner you are using. Some will merely expose a faulty diagnostic issue code, whilst others will let you to select whatever OBD2 code you wish to see and display.

Step 5: Identify And Understand The OBD Codes

Now that the OBD codes have been shown, it’s up to you to figure out what they mean. Unless otherwise specified, every issue code begins with a letter followed by a sequence of four numbers. The letter in the diagnostic problem code may be one of the following:

  • Problems with the engine, gearbox, ignition, emissions, and fuel system are indicated by the letter P (Powertrain). B (Body): Airbags, power steering, and seatbelts are all examples of problems that might occur. C (Chassis): This code indicates that there are problems with the axles, brake fluid, or anti-lock braking system. U (Undefined): Draws attention to concerns that do not fall into the categories P, B, or C.

To understand what a fault code is, let’s look at what the sequence of digits means:

  • Whether the diagnostic issue code is general (0) or manufacturer-specific (1) will be determined by the first number following the letter. It is the second digit that corresponds to a specific car component. The last two digits provide you with the specific problem

Make a note of the OBD codes that are shown by the scanner and then switch off your vehicle. Afterwards, gently disconnect the OBD II scan instrument from the vehicle. Transferring the OBD codes to your laptop through a USB connection or Bluetooth, depending on your scanner’s capabilities, is also an option. When it comes to reading live data from your OBD scanner, you should consult with your mechanic for assistance.

Step 6: Move On To Trouble Code Diagnosis

It is possible to diagnose a problem with your automobile using an OBD scanner or code reader, but it is not possible to determine how to solve the problem. As a result, determine if the error code indicates a minor problem or not. After then, you may choose between a do-it-yourself strategy and expert assistance. However, it is recommended that you send your car to a competent mechanic’s shop in order to prevent making costly mistakes.

Step 7: Reset The Check Engine Light

Once the problems with your vehicle have been resolved, the check engine light should turn off after a short period of driving. However, you may always utilize yourOBD II scan tool to remove a code as soon as it is detected. How? Navigate to the main menu of your OBD2 reader and choose the option for the check engine light. Then hit the Reset button to return to the previous screen. All that should be required is a few seconds or minutes for the engine light to turn off. Note: If the problem isn’t resolved, you may use the scan tool to delete an error code and prevent the check engine light from turning on for a short period of time.

Now that you’ve learned how to utilize an OBD 2 scanner, let’s go over some frequently asked questions.

3 FAQs On How To Use OBD2 Scanner

Following a brief period of driving, the check engine light should go off if the problems with your vehicle have been resolved. It is possible to remove a code quickly using yourOBD II scan tool. How? Then, from the main menu of your OBD2 reader, choose the option for the check engine light. Press the reset button when you’re finished. Give it a few of seconds or minutes, and the engine light should go off on its own. Please keep in mind that you can use the scan tool to delete an error code and temporarily turn off the check engine light if the problem isn’t resolved.

Following your demonstration of OBD 2 scanner operation, let’s go through some frequently asked questions (FAQs).

1. What’s The Difference Between An OBD1 And OBD2 Scanner?

Once the problems with your automobile have been resolved, the check engine light should turn off after a short period of driving. However, you may always use yourOBD II scan tool to remove a code as soon as it appears. How? Locate the check engine light option in the main menu of your OBD2 reader. Then hit the Reset button to return to the previous state. The engine light should switch off after a few seconds or minutes. Note: If the problem isn’t resolved, you may use the scan tool to remove an error code and prevent the check engine light from flashing for a short period of time.

The check engine light, on the other hand, will illuminate again since the problem is still there. Now that you know how to utilize an OBD 2 scanner, let’s go over some frequently asked questions.

  • In order to connect an OBD1 scanner, a cable must be used, but an OBD2 device can be linked over Bluetooth or WiFi.
  • An OBD2 scan tool is compatible with vehicles manufactured in 1996 and beyond, but an OBD1 scan tool is only compatible with vehicles manufactured in and before 1995. As a result, an OBD 2 scanner is more standardized than an OBD 1 scanner.

2. What Are The Different OBD II Scanner Types?

There are several different types of OBD2 diagnostic code readers available. In most cases, though, they may be divided into two types:

1. Code Reader

An OBD2 code reader is a very inexpensive and widely accessible device. It allows you to read and clear any problem codes that may appear. Due to the fact that the OBD2 code reader isn’t the most sophisticated diagnostic equipment available, it is unable to support all manufacturer-specific OBD codes.

2. Scan Tool

A scan tool is a more complicated automotive diagnostic equipment that is often more expensive than a code reader since it can perform more complex calculations. It also includes a plethora of additional functions over and above those of a diagnostic code reader. For example, a scan tool gives you access to previously captured data that you can then review in real time. As an added bonus, unlike a code reader, it also reads the car manufacturer and improved diagnostics codes. In addition to scanners, certain automobile scanner instruments may include diagnostic equipment such as multimeters or scopes.

3. What Things Should You Consider While Buying An OBD2 Scanner?

When purchasing an automobile diagnostic equipment such as an OBD2 scanner, there are several factors to consider:

  • Look for an OBD II scanner that has the most up-to-date technology to ensure compatibility with your future automobiles in the future. A sophisticated OBD2 code reader or scanner equipment will also be able to accurately detect and characterize the nature of your vehicle’s problems.
  • Look for an OBD 2 scanner that is easy to use. (See Resources) A user interface that is welcoming and intuitive will assist you in navigating and reading the OBD codes with ease.
  • Make sure the scanner’s size is comfortable for you to carry if you’re considering a handheld scanner.

Final Thoughts

The OBD 2 scanner is suitable for all users, regardless of whether they use a Bluetooth scanner, a built-in scanner, or a portable scanner that requires a connected connection to the OBD port to function properly. It allows anybody to quickly and affordably identify the need for auto maintenance. The only difficult element is resolving the problem that was found by your auto code reader. You may use Repairsmith to accomplish this. They are a mobile auto repair and maintenance service that can come to you and address your automotive problems on the spot.

You may get out to them seven days a week and take advantage of a simple online booking process.

How to Use an Automotive Diagnostic Tool

If you purchase a product after clicking on one of our affiliate links, TheDrive and its partners may get a commission. More information may be found here. You notice a new, alarming noise coming from your engine, so you open the hood and check about, but you don’t see anything unusual. So, what do you do now? Before you grab for a conveniently located torque wrench to attempt the ol’ “love tap,” connect a diagnostic instrument to the vehicle to gain a little more insight into what’s going on with the vehicle.

When to Use a Diagnostic Tool

Don’t make the mistake of believing that a diagnostic tool is a miraculous answer to all of your vehicle’s problems. It is not. It will not be able to repair a flat tire or replace a windshield. If it occurs, it indicates that the built-in artificial intelligence has become a little too sophisticated.

In reality, when the Check Engine light is up, the most rudimentary diagnostic instruments will merely display meaningless codes to the user. As a result, if you want to get the most out of the tool, you must understand when to employ it.

  • When the Check Engine light is illuminated: Do you remember the light that appears to be on all of the time, even when the engine is not failing? One light on your dashboard might indicate a variety of various issues that can arise in your vehicle’s engine, gearbox, or exhaust systems. For those who like to understand rather than simply ignore this light, a diagnostic tool will be of great assistance
  • Keep track of the vehicle’s performance and statistics: Some higher-end automotive diagnostic instruments are capable of doing functions other than simply reading engine codes. In addition, more complex technologies can capture real-time data readings of the vehicle’s systems to assist you in fine-tuning the configuration.
See also:  P1494 EVAP Leak Detection Pump Switch or Mechanical Fault?

Things You’ll Need

On paper, it appears like diagnosing troublesome issues that your car may detect is very simple. Even if you disregard the high degree of mechanic talent you may require, the specialized tools for working on the vehicle, and the tedious trial and error process that comes with mending a car, all you actually need is a diagnostic tool and an automobile to do the task. gettyimages The use of a straightforward OBD-II tool eliminates the requirement for specialist software.

  • You may use an OBD-II Diagnostic Tool to view the onboard diagnostic codes that your vehicle generates when it identifies a problem. Some scanners are also referred to as “OBD2 scanners” in some listings. Post-1996 Car: Any vehicle manufactured after 1996 will be equipped with an OBD-II port and diagnostic system, allowing it to be used with the diagnostic tool. However, if your vehicle is older than 1996, you may have to identify the problem in the old-fashioned way—by cracking the hood or taking it to a specialist.


Using a diagnostic tool is basically as simple as putting the device into a power source and turning on the computer. Finding the correct port and figuring out how to use the gadget are the two most difficult tasks.

  • Locate the OBD-II port on your vehicle. Typically, it is located anywhere near the steering wheel, beneath the dash, or someplace in between. A few automobiles have the port on the passenger side or someplace in the center console, but this is the exception. For specifics, see the owner’s handbook for your vehicle. Before connecting the automotive scan tool to the OBD-II port, make sure the vehicle is turned off.


Diagnostic tools are often quite similar in terms of both form and function. While some of them have additional features such as sophisticated statistics or reading capabilities, practically all of them are plug-and-scan devices by nature. Thus, there is just one procedure that must be followed in its entirety.

Using a Code Reader

The main concept behind utilizing a diagnostic scan tool is to obtain the diagnostic trouble codes that are automatically recorded by your car when it identifies a malfunction. This is the exact same procedure that mechanics use when you bring your vehicle into a shop, just with far more sophisticated and powerful technology.

Plug the Diagnostic Tool into the OBD-II Port

Instruments for diagnosing Data may be downloaded through the onboard diagnostic (OBD-II) port of a vehicle. This universal access port will provide you with access to nearly everything that the car senses as a problem, regardless of how minor. In order to have access to the information, you must inject some energy into the system.

  • Connect the end connection to the vehicle’s OBD-II port using the provided connector. Make certain that the tool is properly fitted and secure so that it can connect with the vehicle’s onboard computer. Start the engine of the car. If your vehicle retains car codes in its memory, you won’t have to start the engine at all. Depending on whether the engine has to be running in order for the onboard computer to check the vehicle’s health in real time, you may have to start the vehicle from the ground up.

Read the Car Code(s)

The particular codes that your car generates when it identifies a problem are the most important part of the diagnostic procedure. These codes may be downloaded and examined by the diagnostic tool, providing you with some indication of what isn’t functioning. Don’t try to decipher the code yourself; it will appear to be pure nonsense unless you chance to be proficient in the language of “code.”

  • Start the diagnostic tool by pressing the button. Basic tools should be equipped with a straightforward power button located anywhere on the machine.
  • If you have a diagnostic tool that is Bluetooth-capable, switch on the device from the location where it is plugged into the port if it does not turn on automatically.
  • To use the diagnostic scanner, press the button. Some scanners will immediately begin reading the automobile codes as soon as they are turned on. A button or menu item such as “Scan” may be provided to initiate the procedure in other cases.
  • You’ll need to find a Bluetooth-capable scanner that works with an app that’s compatible with it. The majority of them have a built-in app, while some are compatible with third-party applications. If you are using the scanner for the first time on a new car, you may need to enter the vehicle’s VIN number into the scanner.
  • Make a note of the information. After the scan is complete, which usually takes only a few seconds, it will reveal any specific issue or error codes that it has discovered and identified. If the scanner does not provide you with a full explanation of what the code represents, make a note of the codes shown.
  • Some scanners will keep the codes for you, download them to a computer or website, or provide you with an explanation directly on the screen
  • Others will do none of these things. Most scanner apps for Bluetooth-enabled scanners link to a diagnostic service that provides additional information
  • However, this is not always the case.
  • The codes are stored in some scanners for later retrieval, while others are downloaded to a computer or website, or an explanation is provided immediately on the screen. In most Bluetooth-enabled scanning apps, you’ll be sent to a diagnostic service that will provide you with further information.

Interpret the Data

Looking at the issue codes and having no idea what they imply is a common occurrence. That is very natural. You will want a code reader in order to make sense of anything because the difficulty codes will be translated into ordinary terms.

  • Option 1: Look for the issue code on the internet. A simple search using the code will yield the information you want from automobile and/or manufacturer websites
  • Nevertheless, you should consult the manufacturer’s website first. Option number two: Make use of specialist software. A number of third-party computer programs are capable of downloading issue codes from a diagnostic instrument and reading the information directly from a desktop or laptop computer. Option 3: Directly read the information from the diagnostic tool (optional). On the screen of higher-end diagnostic tools, you will be presented with a code description. Some tools provide more information than others, but you should be able to gain a general understanding of the problem that the code represents.

Fix the Problem

Now that you’ve gathered some basic diagnostic information, it’s time to get down to business and repair the problem. It is entirely dependent on your mechanical skill level and expertise to finish this last phase.

  • Option 1: Attempt to resolve the issue on your own. It is likely that if you have any knowledge and expertise in vehicle repair, the fault codes/descriptions you have will serve as an excellent starting point for identifying and repairing the problem
  • Keep in mind that trouble-code notifications are not necessarily connected to the malfunctioning element and may instead be an indication of another problem. Basic diagnostic tools are not the most effective method of resolving difficulties on your own. Automotive mechanics have access to higher-quality diagnostic instruments that monitor a greater number of systems and data
  • Take note that trouble-code notifications are not necessarily connected to the malfunctioning element and may instead be an indication of another problem. If you want to solve problems on your own, basic diagnostic tools aren’t the most effective method. A greater number of systems and information are monitored by higher-quality diagnostic technologies available to mechanics.


  • If you are searching for issue codes on the internet, you should go a bit further to see if there are any common solutions to the problem. Some diagnostic tools are designed to be left connected into the OBD-II port and to provide frequent updates on the health of your car
  • These are known as standby diagnostic kits. If you take your car to a technician after scanning it, bring the codes with you to give the mechanic a head start
  • Don’t reset anything, such as the Check Engine light, until you’ve identified the source of the mistake. In any other case, it will very certainly turn back on later.


One that is not compatible with OBD-II ports, to be precise. Some older vehicles may not have an OBD-I port or do not have one at all.

Q. What issues can an OBD-II scanner detect?

A.It is mostly dependent on the exact diagnostic scanner being utilized. The majority of them are capable of detecting anything that causes the malfunction indication light to illuminate.

Q. Will a diagnostic tool work on non-U.S. cars?

A.It varies from nation to country.

EOBD (European On-Board Diagnostics) systems, for example, are standard equipment in the majority of European automobiles. TO BE CONTINUED READING

  • The Best OBD2 Scanners: Diagnose and Repair Automotive Issues in Record Time These excellent OBD-II scanner alternatives can help you identify those difficult car problems. READ IMMEDIATELY
  • Top Picks for Car Health Monitors: How to Diagnose Your Car with One of the Best Diagnostics may be performed on your vehicle without the need to see a professional using an OBD-II scanner. READ IMMEDIATELY
  • Mechanic’s tool sets that are the best in 2021 (review and buying guide) Always ensure that you have high-quality tools on hand for the work. READ IMMEDIATELY

How to Use a Car Diagnostic Tool or Scanner

Until recently, automobile diagnostic instruments were prohibitively costly. An independent mechanic may expect to pay thousands of dollars for a tool that was only compatible with a single vehicle manufacturer before to 1996. Although onboard diagnostics II (OBD-II) was introduced, professional scan equipment remained to be prohibitively expensive, costing thousands of dollars. Today, you can get a basic code reader for less than the price of a movie ticket, and the appropriate adapter may transform your smartphone into a scanning device.

Before you purchase a car diagnostic kit, keep in mind that they are not a cure for all of your automobile problems.

In the vast majority of situations, it will not inform you what the problem is.

Getty Images/E+/PeopleImages/Getty Images

What Is a Check Engine Light?

When your car’s check engine light on, it is attempting to communicate with you in the only manner it knows how. At its most basic level, the check engine light signals that a sensor (which might be located anywhere in the engine, exhaust, or gearbox) has presented the computer with unexpected data. That might suggest a problem with the system that the sensor is monitoring, a faulty sensor, or a wiring problem in the system. In rare instances, a check engine light may illuminate and then turn off on its own, without the need for external action.

Even after the light has been turned off, information regarding the problem is generally accessible using a code reader.

How to Get a Car Diagnostic Tool

There was a time when code readers and scanners were only available from specialized tool firms, making them impossible to purchase for the typical vehicle owner. Recently, this has changed and you can now purchase affordable code readers and scan equipment from retail tool and parts stores, internet merchants, and other sources, among other places. When it comes to automobile diagnostic tools, if you are not interested in owning one, you may be able to rent or borrow one. Some auto parts businesses may lend you a code reader for free on the condition that you will most likely purchase components from them if you are successful in solving the problem.

For those searching for something more advanced than a simple code reader but who do not wish to spend the money, this may be a viable solution.

The Difference Between OBD-I and OBD-II

In order to comprehend the difference between OBD-I and OBD-II automotive diagnostic tools before purchasing, borrowing, or renting one, you must first understand what they are. Those vehicles that were constructed after the introduction of electronic controls but before 1996 are classified as OBD-I vehicles. Because these systems don’t have much in common between various models, it’s critical to select a scan tool that’s specifically developed for the make, model, and year of your car. Vehicles manufactured after 1996 are equipped with OBD-II, which is a standardized method that streamlines the diagnostic procedure.

Manufacturers can opt to go above and beyond the essentials, resulting in the creation of manufacturer-specific code sets.

Finding Where to Plug a Diagnostic Tool

When you have a check engine light code reader or a scan tool in your possession, the first step in utilizing it is to identify where the diagnostic connection is located. This kind of connector might be found in a variety of locations on older automobiles equipped with OBD-I systems, including beneath the dashboard, in or near the engine compartment, and on or near a fuse block. Diagnostic connections for OBD-I vehicles are available in a range of forms and sizes. Take a look at the diagnostic connector on your scan tool and you should be able to get a fair sense of what to look for in terms of size and form of the diagnostic connector.

The location of the position may differ from one model to another, and it may be difficult to locate.

The connection can be either rectangular or shaped like an isosceles trapezoid, depending on the application.

In certain rare instances, the OBD-II connector may be hidden beneath the ashtray in the center console or in another difficult-to-reach spot on the vehicle.

Using a Check Engine Light Code Reader

After turning off the vehicle’s ignition, carefully put the code reader plug into its diagnostic socket. Assuming that the plug does not go in smoothly, double-check to make sure that it is not upside down and that you have correctly recognized the OBD II connector. Turn on the ignition while making sure the diagnostic connector is properly hooked in. This offers the code reader with more power. Depending on the device, you may be asked for more information at that point. The VIN number, engine type, and other information may all be required to be entered.

At that time, the code reader is fully operational and ready to begin its task. Although the most basic devices just display stored codes, better scan tools provide you the ability to read the issue codes as well as see other information.

Interpreting Check Engine Light Codes

You can note down the issue codes and perform some research if you have a simple code reader on hand. For example, if you see the code P0401, a brief search on the internet reveals that it signals a malfunction in one of the oxygen sensor heating circuits in the vehicle. That doesn’t tell you what’s wrong with your computer, but it’s an excellent place to start looking. More sophisticated scan tools may be able to tell you exactly what the error code implies. Depending on the situation, it may even present you with a troubleshooting technique.

See also:  AC blows warm Toyota Sequoia?

Next Steps

Regardless of whether you have a basic code reader or a high-end scan tool, the next step is to figure out why the issue code was set in the first place, and then fix the problem. The quickest and most straightforward method is to seek up probable reasons and rule each one out one at a time. If you can locate a real-life troubleshooting technique, that would be much more beneficial. In the previous example of a P0401 fault code, additional inspection indicates that the oxygen sensor heating circuit in bank one sensor two has failed due to a failure in the circuit.

An initial step in troubleshooting in this situation is to examine the resistance of the heating element, which will either confirm or rule out the presence of a problem, and then inspect the wiring.

If this is not the case, the diagnostic process would proceed.

Finishing the Job

In addition to reading codes, the majority of check engine light code readers are capable of performing a number of other critical tasks. An example of such a feature is the option to remove any previously saved trouble codes, which you should do after attempting to fix the vehicle. In this method, if the identical code reappears later on, you’ll know that the problem hasn’t been resolved. Even when the engine is operating, certain code readers and all scan tools have the ability to acquire live data from a number of sensors.

It allows you to examine the information from a specific sensor in real time, which is very useful in emergencies.

This type of monitor will automatically reset when the codes are cleared or when the battery is removed from the unit.

Before going through the emissions process, it’s a good idea to check the status of the readiness monitors to make sure they’re operational.

Using a Diagnostic Car Code Reader


Fix-It-Up-For-The-Family With an auto code reader, you can diagnose automotive problems without having to take your vehicle to a specialist. Simply connect it to the computer system of the vehicle and analyze the fault code readout that appears.

Use the car code reader as a starting point

Connect your automobile code reader to the diagnostic link connection, which is located beneath the dashboard (engine off). Then start the car and follow the auto code reading process outlined in the owner’s handbook to complete the task. Nothing may throw your day off track more quickly than the appearance of the “Check Engine” light on your dashboard. You’re debating whether you should pull over and turn off your car or continue driving to the nearest business. An engine code reader/scanner can assist you in making the option to drive or not to drive, as well as in diagnosing and correcting the problem.

  • However, it is not a magic bullet that will always tell you precisely what is wrong with you.
  • A simple automobile code reader device that produces an alphanumeric fault code but no information about what it implies is the least expensive type of auto code reader unit available.
  • P0115 Engine Coolant Temperature Circuit Malfunction” is a common error message on mid-priced machines, which means that the fault is truly displayed on the screen.
  • However, if you are a genuine grease monkey, you should invest in a more costly scanner.
  • That eliminates the need to dive beneath the hood (with a wiring schematic in hand) and pierce cables and take sensor readings.
  • There’s a little more to it than that, though.
  • How did you find out?
  1. Check the manufacturer’s Web site to see if it has any information about the issue code that you are experiencing
  2. Make use of discussion forums on the internet. Simply do a search for your vehicle’s model and include the word “forum” in the search query. Register for the site (it’s typically free) and submit your query, including the year, mileage, code number, and what you’ve done so far with your vehicle in the comments section. When it comes to the amount and quality of answers you receive, you will be pleasantly pleased. Subscribe to a shop handbook that is available online. It will contain not only a list of all of the carmaker’s technical service bulletins, but it will also contain the whole diagnostic method for the code in question. It will guide you through the testing procedure, instructing you on which cables to check and what voltages you should be looking for. Additionally, component locators are available to assist you in locating the item in your car, and wiring diagrams are available to indicate the connection position for each wire.

Required Tools for this Project

It is necessary to have a code reader or scanner, as well as a computer with internet connectivity, in order to decipher the problem codes.

Using a Scan Tool to Diagnose Your Car

It’s time for the state inspection, and you’re prepared to leave the house bright and early in the morning in the family’s 1998 minivan for the inspection station. You’re not in a very upbeat frame of mind this morning because your daughter informed you that “the light went on” on the way home last night. She claimed she had put a few dollars worth of petrol in the tank in order to make it home. It turns out that your displeasure was unfounded. Sure enough, the light is illuminated, but it isn’t the fuel warning light; rather, it is the Check Engine warning light.

Regardless of whether the minivan has a full tank of gas, it does not pass muster.

This Instructable will teach you how to utilize scan tools to diagnose the problems with your automobile.

Before driving your automobile to a technician, you should learn how to do the fundamentals yourself. This project was first featured in the August 2001 edition of Popular Mechanics, and it has since been updated. At Popular Mechanics DIY Central, you can find even more interesting ideas to try.

Step 1: Use an OBD II

This is a late-model car equipped with what is known as OBD II, a second-generation on-board diagnostic system that began replacing OBD I in 1994 and has been in use ever since. It is a nationally regulated standard that applies to the whole business. One of the difficulties with OBD II for the do-it-yourselfer is that you can’t retrieve trouble codes by counting the blinks of the Check Engine light, as you could with previous computer-controlled vehicles. Another difficulty with OBD II is that it doesn’t work with older computer-controlled automobiles.

  1. Alternatively, you may learn about OBD II on your own; however, you will require a piece of diagnostic equipment that you most likely do not already possess—an OBD II scan tool.
  2. When using OBD II, that indicator will only illuminate if there is a fault that has a major impact on emissions.
  3. Many difficulties result in the LED remaining illuminated after the repair has been completed, with the code remaining in the computer’s memory for a certain number of ignition on/off cycles.
  4. It is possible that the light may eventually go out and the code will self-erase, possibly after the next time you start and stop the automobile.
  5. When dealing with many other issues, however, the scan tool is the sole method to turn off the light and wipe the code completely.
  6. As a result, if you bring your car in for a state inspection before you’ve done enough typical driving, it’s possible that the computer hasn’t finished all of its testing and your car will fail inspection as a result.
  7. So, when the expert comes to inspect your vehicle, you will have a better knowledge of what he or she is looking for.

Step 2: Cracking the Code

An OBD II scan tool can also read a limited amount of engine operating data, typically including rpm, ignition timing, fuel-injection calibrations, readings from a variety of sensors (including the oxygen, throttle position, barometric, and mass airflow sensors), a “calculated load” value, and occasionally switch position signals.

There is also a “capture” option in OBD II that allows you to use the scan tool to obtain a “picture” of what the sensors were reading at the precise moment the driveability problem occurred.

Step 3: Sensor Scan

Because of the expanded scan tool capacity, you can detect problems that do not result in the engine warning light turning on. On a late-model automobile, for example, we discovered a generic PO713 code that was previously unknown. “Transmission fluid temperature sensor circuit—high input,” according to the shop manual, describes this circuit. If the transmission fluid becomes very heated while in use, the transmission may fail totally and very fast. If a scan tool offers improved diagnostics, it might save a great deal of time and work for the user.

With a single click of a button on the code tester, we were able to clear the code.

Once more, we cleansed the area before taking a look at the reading from the gearbox temperature sensor that was sent to the powertrain controller.

The sensor or the circuit, or even a poor connection, appeared to be the source of the problem.

Step 4: Scan Tool Choices

If you have a late-model vehicle, it is equipped with OBD II technology. To be clear, just because it’s generic and any OBD II scan tool’s wire connector will plug into your vehicle, it doesn’t follow that any OBD II scan tool will operate on your vehicle. Since the newest European models (1998 and after) require a software upgrade, they are the source of the problem. Korean automobiles are similarly troublesome, and the extent to which they may be scanned with a specific scan instrument must be determined on a case-by-case basis.

  • With the use of a plug-in cartridge, the Actron ScanTool for OBD I may be upgraded to the same degree of OBD II functionality as the OTC Mind Reader (or you can buy an OBD II-only model).
  • Despite the fact that it lacks the OBD I Chrysler command tests included in the Mind Reader, it is the only home mechanic’s scan tool we’ve tested so far that covers all generic OBD II vehicles (including European models), with more models on the coming in the future.
  • If you purchase an optional cable from the manufacturer, you will be able to keep the file on your own computer and subsequently download it to your scan equipment from there.
  • Despite the fact that professionals have had all of this software (and much more) in their scan tools for some time, you will have to wait for it to become available in the general consumer market.
  • Despite the fact that Actron offers a variety of OBD II scan instruments, the Actron CP9087 is the company’s most popular tester for car owners.
  • There are no sensor readings or other data items available to you.
  • It includes a nice selection of wire leads for establishing test connections, as well as a back-probe adapter that has a thin, curved metal termination.
  • OBD II is entering its sixth full year of operation, and the cars equipped with this system that were manufactured prior to that date are no longer covered by warranty.

A significant improvement has been made in the ability of the OBD II powertrain computer to detect faults and log code information. However, until you connect a scan tool to the computer, it will provide you with no information.

Step 5: How OBD II Transmits Data

Powertrain computers are now at the center of a vehicle’s communications network, transferring information from switches and sensors to other computers that operate antilock brakes, air conditioning, gearbox, suspension, and safety systems, among other functions. Due to the fact that the powertrain computer is also in charge of systems that have an impact on engine emissions, the information it processes must be accessible to a technician for examination. This information is transmitted by a wire to a conventional 16-terminal diagnostic connection (although, generally, fewer than a half-dozen terminals are live in any given vehicle).

Fortunately, there has been some standardization, but we are not yet at the point where we can use a single transmission protocol for all vehicles, which is the source of the difficulty with late-model European vehicles (including the Cadillac Catera).

Every family PC owner is aware that “plug and play” doesn’t always work, and OBD II scan equipment might experience compatibility issues when used with certain vehicles.

What criteria do you use to determine this?

Be the First to Share

The items and services that we write about are chosen by our editors. If you make a purchase after clicking on one of our links, we may receive a commission. After following this step-by-step guide, you will be able to perform diagnostics on your vehicle’s systems using an OBD-II scan tool. You’ve noticed that your check engine light has come on?

  • A car nowadays is quite complicated, therefore it’s important to have an OBD-II scan tool to assist you in diagnosing and fixing the problem.
  • Have you never used one before?
  • It’s not an issue.
  • More information may be found at: Mechanic The BlueDriver Bluetooth Pro OBDII Scan Tool Receives an Unbiased Review In this post, you will learn how to utilize an OBD-II scan tool to diagnose your vehicle.

The following is a step-by-step instruction on how to use an obd2 scanner to diagnose your car.

Step 1: Find the diagnostic link connector (DLC) on your vehicle.

In most cases, this is a triangular-shaped connection that may be found beneath the steering column. If you are unable to locate it for whatever reason, consult your owner’s handbook or conduct a fast web search to determine what you are searching for.

Step 2: Plug in the OBD-II tool into the DLC.

Turn the key to the ignition position once it has been fully inserted. However, do not start the engine. As soon as the scan tool begins to communicate with the internal computers in your car, you will begin to see a series of messages on the display screen. If you are unable to see anything on the screen for any reason, check to confirm that it is properly connected. The OBD2 connection is used.

Step 3: Enter the information as requested on the scanner screen.

Included in this may be the Vehicle Identification Number (VIN) as well as other basic information about your automobile. Every OBD-II scan tool is different in terms of the quantity of information that has to be entered. This phase differs depending on the type of scanner being used. Some will just show you the troublesome codes, while others will allow you to pick and select whatever codes you wish to view, depending on your needs.

Step 5: Figure out what the codes mean.

The codes should be nearly same regardless of whether the displays are different or identical. They will most often begin with the letters P, B, C, or U as a starting point (Powertrain, Body, Chassis, and Undefined).

  • When you see a number following the letter, it corresponds to the manufacturer of the car. As an example, the second number refers to a specific component of a vehicle, such as the transmission
  • In this case, the last two digits correspond to the specific problem that is occuring

As a result, you’ll need to consult an online code chart in order to obtain that information.

Step 6: Proceed with the diagnosis.

When it comes to understanding automobiles, it takes a certain level of expertise to figure out what is wrong. When you run the code, it will tell you what’s wrong, but it will not always tell you what you need do to repair the problem. You have two options at this point: either take your vehicle to a licensed mechanic’s shop for repair or conduct some research on your own to see whether the problem is something you can fix yourself. It is possible that the problem is only a blown fuse that may be easily replaced.

See also:  Radiator fan runs after shutdown, drains battery?

Step 7: Reset the check engine light.

After your car has been repaired, the check engine light should go off after you have driven it for a short period of time. However, if you want to get rid of it right immediately, you may do it with the help of your OBD-II scan tool. Simply navigate to the main menu and select the check engine light option, after which you will push the reset button. Once the light has been turned out for a few seconds or minutes, you should be on your way! How to properly operate an OBD2 scan tool

The bottom line

The usage of an OBD-II scan tool is not complicated, as you can see in the video below. If you follow these basic procedures, you should have no trouble determining the source of the problem with your car. If you encounter any difficulties, you may bring your car and the scanner to any auto parts store and they would be happy to assist you.

The scan tool itself is a sophisticated piece of equipment, but fortunately, it is not difficult to use for the typical person! Bonus: A Detailed Buying Guide for the Best OBD2 Scanners in 2021 is included.

How to Read and Understand OBD Codes

Documentation Download Documentation Download Documentation You’re riding down the road, taking in the scenery, then all of a sudden the most enigmatic of indications illuminates: “Check Engine.” What does this mean? What exactly does it mean? Considering that the engine is a massive and sophisticated mechanism, just “checking the engine” is not likely to yield many results. In this case, a vehicle’s OBD-II code reader comes in handy. This little gadget will allow you to pinpoint exactly where the issue is originating from on your computer.

  1. 1 Obtain an OBD-II scan tool for your vehicle. OBD-II scan readers are available from a variety of sources, including internet and auto-parts retailers. With a Bluetooth-capable smartphone, you may download an app to analyze the data and purchase an OBD reader, which will display the codes and explanations straight on your smartphone.
  • It is necessary to acquire an OBD-I scanner if your automobile or light truck is older than 1996. OBD-I scanners are more vehicle specific and do not use the universal OBD-II coding system, therefore you will need to purchase one. The OBD-II system is the subject of this article
  • The OBD-II system continuously checks the operation of your engine and Emissions Control System (ECS). It will illuminate your Check Engine Light anytime a problem occurs that causes the vehicle’s generated emissions to be more than or equal to 150 percent of the Federal Environmental Protection Agency’s mandated levels.

2Find the Diagnostic Link Connector (DLC) in your vehicle’s electrical system. This is a 16-pin connection with a triangle design that is often found beneath the left hand side of the dashboard, near the steering column. If you are having problems discovering the DLC, you may look for it on the internet by entering the model and year of your automobile, or you can consult your owner’s handbook. Advertisement 3 Connect the scan tool connection or code reader to the DLC using the DLC connector or code reader.

Your vehicle’s onboard computers will begin to communicate with the scanner as soon as it starts communicating with them.

  • Alternatively, if the screen remains blank and the DLC connector does not illuminate, jiggle the connector to ensure greater contact between the scanner and DLC connector pins. Older automobiles, in particular, may have inferior connections
  • If you’re still having trouble, check to see if your cigar lighter is functional before proceeding. This is due to the fact that the DLC is powered by the cigar lighter circuit, which is used by the OBD-II system. To determine whether the cigar lighter is not working, find and inspect the relevant fuse.

4Input the information about your car. Some scanners may want you to enter your VIN as well as the make and model of the car, which can be time-consuming. It is possible that you may be required to identify the engine type. The procedure will differ based on the scanner used. 5 Look for the menu. Upon completion of the scanner’s boot-up process, check for a menu. To access the main Codes menu, select “Codes” or “Trouble Codes” from the main menu bar. Depending on your scanner and the year of your car, you may be provided with a number of systems such as the engine/powertrain, transmission, airbag, and brakes, among others.

The most often seen codes are Active codes and Pending codes.

  • Active codes are problems or codes that are now active and causing your Check Engine Light to illuminate. The fact that your Check Engine Light is off does not imply that the code or fault has been resolved
  • Rather, it indicates that the circumstances that triggered the code have not been met for at least two consecutive operations of the vehicle. Pending codes indicate that the OBD-II monitoring system has failed to operate an emission control system at least once, and if it fails to operate the system again, the Check Engine Light will illuminate and the failure will be classified as an Active code.
  1. 1 Find out what the letter represents. Each code will begin with a letter that denotes the system the code is referring to, followed by a number. Although you may have to navigate to different menus in order to view them, there are a number of letters that you may encounter:
  • P stands for powertrain. This includes topics such as the engine, transmission, fuel system, ignition, emissions, and other aspects of the vehicle. This is the most comprehensive collection of codes
  • B-Body type. This includes airbags, safety belts, electric seats, and other features. C stands for chassis. These codes cover a wide range of topics, including ABS, brake fluid, axles, and more. U stands for undefined. These codes cover a variety of additional components of the automobile

2 Learn what the statistics signify by reading this article. P0xxx, P2xxx, and P3xxx are all generic codes that apply to all types and models of automobiles, including motorcycles. P1xxx codes are peculiar to a certain manufacturer, such as Honda, Ford, Toyota, and so on. The second number indicates the subsystem the code is associated with. P07xx codes, for example, are associated with transmission.

  • The final two digits of the code represent the exact problem that the code is referring to. For more information about each unique code, see a code chart online.

3 Take a look at an example of code. P0301 indicates that cylinder 1 is experiencing a misfire situation. When a P is present, it indicates that it is a powertrain code, whereas a 0 indicates that it is a general or universal code. The number 3 indicates that the region or subsystem is a code for the Ignition System.

  • The 01 indicates that there is a misfire situation in the number 1 cylinder, which implies that it is a cylinder-specific problem. A worn-out spark plug, plug wire, or specialized ignition coil, or a vacuum leak near the cylinder, might be the cause of this condition. No specific component is identified by a code
  • Rather, the code points to or implies that a component, its circuit, or its wiring/vacuum control are failing. The code may be an indication of a problem caused by an entirely different system from the one that generated it.

4 Perform an inspection on your car. It takes years of training and experience to be able to correctly diagnose OBD-II codes. Example: A weak battery or an alternator that has become obsolete might cause five or more codes to be set in systems that are otherwise totally normal.

Consider the following before beginning any repairs: the codes will not inform you what parts need to be replaced or what repairs need to be performed on their own.

  • Instead of attempting to repair your car yourself, take your vehicle to an ASE Certified Master Technician who has earned the L1 Advanced Engine Performance Diagnostic certification, or you might wind up losing a lot of time and money.

5 Reset the Check Engine Light on your vehicle. The majority of OBD scanners allow you to reset your Check Engine Light once you’ve completed your repairs or simply don’t want to see your Check Engine Light for a time. A specific amount of driving time will be required before the light will turn off completely (this varies from manufacturer to manufacturer).

  • Most scanners have a button on the main menu that allows you to reset the Check Engine Light. It is also referred to as a CEL in some circles.

Create a new question

  • Question What is the best way to decipher OBD codes? Ed Beery is an automotive specialist and the owner of InTechgrity Automotive Excellence in Denver, Colorado. He has over 20 years of experience in the automotive industry. He has more than eight years of expertise in offering maintenance and repair services to both people and businesses. Eddy and the Automotive Excellence Team at InTechgrity have been approved for repairs by the American Automobile Association (AAA) and have earned the Automotive Service Excellence (ASE) certification. Expert in the Automotive Industry Answer You may look up the code on the internet. As well as probable reasons and remedies, this can assist you in deciphering the code and understanding its significance. Question What is the location of my OBD port? Ed Beery is an automotive specialist and the owner of InTechgrity Automotive Excellence in Denver, Colorado. He has over 20 years of experience in the automotive industry. He has more than eight years of expertise in offering maintenance and repair services to both people and businesses. Eddy and the Automotive Excellence Team at InTechgrity have been approved for repairs by the American Automobile Association (AAA) and have earned the Automotive Service Excellence (ASE) certification. Expert Answer from an Automotive Specialist Look behind the dash on the driver’s side for hidden treasure! This is the location of the majority of OBDII ports. Question What exactly is an OBD gadget for a car? Ed Beery is an automotive specialist and the owner of InTechgrity Automotive Excellence in Denver, Colorado. He has over 20 years of experience in the automotive industry. He has more than eight years of expertise in offering maintenance and repair services to both people and businesses. Eddy and the Automotive Excellence Team at InTechgrity have been approved for repairs by the American Automobile Association (AAA) and have earned the Automotive Service Excellence (ASE) certification. Expert Answer from an Automotive Specialist An OBD device, also known as an OBDII scan tool, is a device that allows you to retrieve codes from a vehicle’s OBDII port. Question: What is an OBD device? What is the difference between OBD and OBDII? Ed Beery is an automotive specialist and the owner of InTechgrity Automotive Excellence in Denver, Colorado. He has over 20 years of experience in the automotive industry. He has more than eight years of expertise in offering maintenance and repair services to both people and businesses. Eddy and the Automotive Excellence Team at InTechgrity have been approved for repairs by the American Automobile Association (AAA) and have earned the Automotive Service Excellence (ASE) certification. Expert Answer from an Automotive Specialist OBDII is the most recent automobile connection protocol to be developed. Earlier versions were known as OBD, and they were superseded between 1994 and 1996
  • Question What is the difference between bank 1 and bank 2? Norm Glitz Answer from the Community Inline engines, such as the majority of four-cylinder engines, only have bank one and no bank two. An inline 6 (which is becoming increasingly rare these days) may have two banks: bank one in the front and bank two in the back. A V-6 engine’s bank one is normally the side of the engine whose connecting rod is first in line on the crankshaft, as shown in the diagram below. On most engines, this is difficult to discern. The basic catalytic converters and associated oxygen sensors are what the banks are truly referring to. Prior to the cat, there is an oxygen sensor. That one adjusts or lowers the fuel-to-air ratio of the engine in order to reduce harmful emissions. There’s another one just after the cat. This one keeps track of the cat’s productivity
  • Question In what context does the OBD code PO128 appear? When determining whether or not the engine has reached a “normal” temperature, the length of time the vehicle has been running, the readings from the intake air temperature (IAT) sensor, the reading from the engine coolant temperature (ECT) sensor, and the speed of the vehicle are all taken into consideration
  • Question What exactly does the code PO446 mean? A code P0446 might indicate a malfunctioning vent valve. Question P0320 was the code I obtained from the scanner. What exactly does this imply? Jessie BrooxAnswer from the Community Malfunction in the input circuit for the ignition/distributor engine speed. Incorrect Ignition/Distributor engine speed sensor readings, incorrect Ignition/Distributor crankshaft position readings, engine speed sensor harness that is open or shorted, incorrect Ignition/Distributor engine speed sensor circuit, poor electrical connection, low battery charge, incorrect Engine Control Module (ECM) readings are all possible causes. Question What do the codes p0420, p0456, and p0137 mean? What do these codes mean? Typically, p0420 indicates a faulty catalytic converter or front or rear O2 sensor
  • P0456 indicates an EVAP leak
  • And p0137 indicates a faulty O2 sensor as well. Question What does the Fault symbol on my OBII scanner represent? Diagnostic trouble codes (DTCs) are used to identify faults. There is a detailed explanation for each one so that the user may comprehend what is wrong with the vehicle.

More information on the replies Inquire about something There are 200 characters remaining. Include your email address so that you may be notified when this question has been resolved. SubmitAdvertisement

  • A code reader’s capabilities are confined to two things: reading codes and clearing codes. The diagnostic monitors do not give real-time data or inform you of which diagnostic monitors have failed or completed successfully. Scan tools, which are more expensive and more difficult to use, can scan codes, offer detailed information about code details, read and show live data, and assist in the confirmation of diagnoses.


  • Do not assume that the code will inform you which part has to be repaired or replaced. Despite the fact that the polite but inexperienced auto parts salesperson will be eager to recommend a variety of items to test, this can become quite expensive and even obfuscate the issue
  • Following the completion of repairs, a proper drive cycle must be completed in order to clear all of the readiness monitors. Consequently, an emission test can be done and passed if necessary


About This Article

To read OBD codes for vehicles built after 1996, you’ll first need to acquire an OBD-II scanner and attach it to your car’s Diagnostic Link Connector, which you can discover by reading either the internet or your owner’s handbook. Article SummaryX In order to start the connection, turn on the ignition without starting the engine and browse to the scanner’s code selection menu. Consult a code chart if you see any “active” or “pending” codes, since this will provide you with additional information about what and where the fault is occurring.

Did you find this overview to be helpful?

Did this article help you?

Leave a Comment

Your email address will not be published. Required fields are marked *