P2138 Reduced Power on GM vehicles? (Suits you)

  • The P2138 Reduced Power bulletin applies to the following vehicles: 2005-2011 GM Passenger Cars and Light Duty Trucks (Including Saturn) The P2128 trouble code refers to Accelerator Pedal Position (APP) Sensor 1-2 Correlation. What does trouble code p2128 mean on a GMC Sierra?

How do I fix error code P2138?

What repairs can fix the P2138 code?

  1. Replacing the throttle body motor or throttle body assembly.
  2. Repairing or replacing wiring that is associated with the throttle body motor.
  3. Replacing the throttle position sensor.
  4. Repairing or replacing wiring that is associated with the throttle position sensor.

Can you drive with a P2138 code?

We recommend addressing the issue causing P2138 as soon as possible. Your car may have trouble accelerating or go into reduced power mode when this code is triggered, which lets you know it’s not the best idea to drive with P2138.

How do I know if my accelerator pedal position sensor is bad?

Bad Accelerator Pedal Position Sensor Symptoms

  1. Your car hesitates to move when the gas pedal is pressed.
  2. Rough Idle.
  3. Your car doesn’t accelerate over a specific limit.
  4. Your car won’t shift up or jerks upon depressing the pedal.
  5. You experience low gas mileage.
  6. Check Engine Light.

What does error code P2138 mean?

Diagnostic trouble code (DTC) P2138 stands for “ Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation.” It is triggered when the vehicle’s engine control module (ECM) or powertrain control module (PCM) detects that the signals from the two throttle position sensors (or two accelerator pedal position sensors) do

Can I drive with a bad throttle position sensor?

Can you drive with a bad throttle position sensor? It is not a good idea to drive with a bad throttle position sensor. Driving your car in this condition can be dangerous because your car might not accelerate properly or could suddenly accelerate without the driver pressing the gas pedal.

How do you reset the throttle position sensor?

The easiest way to reset your throttle position sensor is to unhook the negative cable from your battery for up to five minutes or to remove the fuse for your engine control module.

How much does it cost to fix TPS?

What is this? The parts will cost you between $75 and $130 on average. The labor costs will be anywhere between $60 and $90, depending on the hourly rate of the mechanics. So in total, you can expect to pay between $135 and $220 for a throttle position sensor replacement.

What does the app sensor do?

APP sensor serves as a determiner and connector between the driver and the ECU – basically the brain of a vehicle. It signals the ECU to allow more air-fuel mixture ratio to the engine through the throttle body in accordance with the gas pedal position.

How does accelerator pedal sensor work?

The accelerator pedal position sensor works by using a Hall Effect sensor that determines the location of the pedal by a magnetic field. It produces a change in the charge based on a change in the position of the pedal. The information is relayed to the ECM to let it know how hard you are pushing on the gas pedal.

What happens when your accelerator pedal sensor goes out?

If the accelerator pedal sensor fails, the following fault symptoms may occur: Increased engine idling speed. Vehicle does not respond if the accelerator pedal is pressed. Engine warning light in the cockpit illuminates.

Where is the accelerator sensor located?

The sensor is usually located on the butterfly spindle/shaft, so that it can directly monitor the position of the throttle.

What is a throttle pedal position sensor switch?

On an Electronic Throttle Control (ETC) system, the PCM keeps track of throttle plate position and uses input from two or in rare cases, three throttle position (TP) sensors mounted on the throttle body and a pair of accelerator pedal position (APP) sensors connected to the accelerator pedal.

Why does the throttle position sensor Get Low voltage?

The voltage of the throttle position sensor can drop below the expected range for several reasons, including the following: A loosely-mounted throttle position sensor. Electrical short on the sensor circuit, either to the ground or to another wire. Bad or corroded wiring or connections for the sensor.

How do I fix code P0223?

What repairs can fix the P0223 code?

  1. Replacing the throttle position sensor.
  2. Replacing the Engine Control Module.
  3. Plugging in, repairing, or replacing wiring that is associated with the throttle position sensor.
  4. Repairing or replacing the throttle body.
  5. Realigning the throttle position sensor.

P2138 Code GM Engine

An intermittent malfunction indicator light (MIL) lit with a message or an indicator that reads Reduced Engine Power may cause some consumers to express their dissatisfaction with the vehicle. On a scan tool, the technician can see the DTC P2138 – Accelerator Pedal Position (APP) Sensor 1-2 Correlation set to either Current or History, depending on the scanner.


General Motors Passenger Cars and Light-Duty Trucks from 2005 to 2015. More information is available by clicking here. This bulletin has been updated to include more model years, to conform to the Global Labor Code (GLC), and to delete the Warranty Information (Saab U.S. Models) part, which was previously included. Please do not use the Corporate Bulletin Number 07-06-04-019D any more.


An intermittent malfunction indicator light (MIL) lit with a message or an indicator that reads Reduced Engine Power may cause some consumers to express their dissatisfaction with the vehicle. On a scan tool, the technician can see the DTC P2138 – Accelerator Pedal Position (APP) Sensor 1-2 Correlation set to either Current or History, depending on the scanner.


A water incursion through the instrument panel (IP) to body harness connector, which is responsible for transmitting the APP sensor signals to the ECM/PCM, may result in this problem. As a consequence of the water incursion, there is an increase in the voltage differential between APP Sensor 1 and APP Sensor 2 that exceeds a specified value for a length of time that has been calibrated, resulting in the setting P2138.


NOTE: Aftermarket equipment may cause DTC P2138 and/or additional DTCs to be generated. 1.Inspect for electrical connections to any of the APP sensor signal or low reference circuits, as well as any additional ECM/PCM 5V reference or low reference circuits. 2.Complete the Diagnostic System Check – Vehicle procedure. A.If any 5V reference DTCs are set, consult the Diagnostic Trouble Code (DTC) List – Vehicle for further information. To proceed to Step 3, check to see if any 5V reference DTCs are not set.

  1. 4.Check the surrounding area for signs of a water leak.
  2. If a water leak is discovered, it should be repaired immediately.
  3. 5.Check the connecting terminals of the IP to body harness connector for corrosion and debris.
  4. 6.After finishing the repair, test the system to ensure that it is functioning properly.

P2138 Reduced Power on GM vehicles

To resolve the P2138 Reduced Power problem, General Motors has published a technical service bulletin07-06-04-019D.

The P2138 fault code, as well as a check engine light, may be kept in the computer by the manufacturer. Bulletin P2138, Reduced Power, is applicable to the following models of vehicles:

07-06-04-019D has been updated to07-06-04-019E and includes more vehicles and more troubleshooting,Find the updated bulletin here

General Motors Passenger Cars and Light Duty Trucks from 2005 to 2011. (Including Saturn) HUMMER H2 (2005-2009)2006-2010 HUMMER H3 (2005-2009)2005-2009 Saab 9-7X (2005-2009) When the P2128 fault code is shown, it means that the Accelerator Pedal Position (APP) Sensor 1-2 Correlation has occurred. Assembly for measuring the location of the accelerator pedal Do not automatically assume that your accelerator pedal sensor is faulty. According to GM, the situation is caused by water leaking into the body harness connector, which is responsible for transmitting the APP signal to the PCM.

  1. It is possible, however, for this code to be created as a result of the installation of aftermarket equipment that is plugged into the incorrect wire (radio, remote starter, radar detector, etc).
  2. Sunroof drains that have become blocked, A-pillar leaks, windshield or cowling leaks are all examples of how water might get into the connection.
  3. The connector should then be dried out, dielectric grease applied, and the connector reseated.
  4. 2015, 2015, 2015, 2015, 2015, 2015, 2015, 2015, 2015, 2015 Rick Muscoplat is a professional musician.
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What’s Up With Chevy’s Engine Power is Reduced Warning?

Customers driving early model years of the 9th generation Malibu and 1st generation Cruze have reported receiving a large number of warning messages stating that their vehicle’s ‘ Engine Power is Reduced,’ which can soon result in a loss of power and reduced acceleration while driving. As this 2016 Malibu owner can confirm, it’s downright dangerous: I can be driving down the freeway in heavy traffic when my car abruptly loses power, almost causing me to get struck from behind. It’s horrible and hazardous, and I’ve spoken with Chevrolet dealerships about possible recalls.

What’s Triggering the Warning Message?∞

According to the investigation, the problem appears to be connected to malfunctioning electronic throttle control and accelerator pedal sensors. It is no longer necessary to physically link the accelerator pedal and throttle with a cable, as was the case with older drive-by-cable systems. An intricate web of sensors and electronic control units (ECUs) known as a drive-by-wire system takes their place, and it is extremely complex. These modern systems have their advantages, but they are also known to induce delayed acceleration and to be more susceptible to intricate electrical failures than older systems.

Warning is usually accompanied by these error codes∞

Here are a few examples of frequent fault codes for pedal position sensors:

  • The code P0122 indicates that the Switch A Circuit in the throttle position sensor is at a low voltage. The code P0223 indicates that the Switch B Circuit in the throttle position sensor is activated. When the codeP2138 is shown, it indicates that there is a problem with the D and/or E circuits of the throttle position sensor.

Malibu Accelerator Sensor Lawsuits∞

The electronic throttle controls and the accelerator pedal position sensor are intended to survive for the whole life of the vehicle in which they are installed. However, so far, General Motors’ response has been appalling. In most cases, even when error codes are generated and point to a specific issue, owners are left to foot the tab for any necessary repairs.

A number of lawsuits have been filed against the company, with the plaintiffs claiming that their vehicles are unsafe to drive for both themselves and other drivers on the road.

An investigation for another potential class-action lawsuit∞

In addition to the 2016-2019 Chevy Malibu, the 2017-2018 Buick LaCrosse, and the 2018 Buick Regal, the law firm of MigliaccioRathod is now researching engine power reduction concerns that result in sudden slowdown, typically while traveling at highway speeds. An accelerator pedal sensor that looks to be malfunctioning appears to be the source of the problem. If you have encountered difficulties with your Chevrolet vehicle’s engine power, please contact the attorneys at MigliaccioRathod by clicking here and filling out a brief contact form on the next page.

P2138 problems

It is being investigated by the law firm of MigliaccioRathod for engine power reduction concerns that cause sudden slowdown, typically when driving at highway speeds, in the 2016-2019 Chevrolet Malibu, the 2017-2018 Buick LaCrosse and the 2018 Buick Regal. An erroneous accelerator pedal sensor appears to be to blame for the problem. For more information on how to contact the attorneys at MigliaccioRathod if your Chevrolet car has suffered reduced engine power problems, please click here to complete out a brief contact form.

P2138 DTC Throttle/Pedal Pos Sensor/Switch D

Don Bowman contributed to this article. ASE Certified Automotive TechnicianThrottle/Pedal Pos Sensor/Switch D / E Voltage Correlation ASE Certified Automotive Technician

What does that mean?

This diagnostic problem code (DTC) is a general powertrain code that may be seen on many vehicles. Although particular repair processes may alter significantly depending on the model, it is called general since it applies to all makes and models of automobiles manufactured after 1996. It is possible that the throttle will not open and shut properly if the throttle/pedal position sensor/switch D/E voltage correlation is set in the automotive trouble codeP2138. In the 1990s, vehicle manufacturers began using ‘Drive by wire’ throttle control technology on a large scale across the industry.

Previously, the vehicle’s throttle was operated by a simple cable that connected the gas pedal directly to the throttle.

When the throttle is moved or positioned, the TPS transforms it to a voltage signal, which is then sent to the engine management computer, which utilizes the fluctuating voltage signal to formulate an engine management plan.

Although the code has the same frame of reference as the other codes, the wording on certain manufacturers is significantly different, such as ‘Throttle position sensor circuit range/performance’ on an Infiniti or ‘Electronic throttle control system malfunction power management’ on a Hyundai, for example.

  • As a result, the computer transmits a voltage to the electric motor, which causes the throttle plate to be released.
  • An illustration of a throttle body; the throttle body position (TPS) sensor is shown in the lower right corner of the image.
  • When both voltages are in agreement, the system is in proper working order.
  • Additional difficulty codes may be generated in conjunction with this code, which will help to pinpoint the source of the problem.
  • Here is a shot of an accelerator pedal, complete with sensor wire attached to its surface: Panoha (Own work) provided permission for use of his photograph, which was obtained from Wikimedia Commons.

NOTE: Because this P2138 DTC is essentially the same as the P2135, P2136, P2137, P2139, andP2140 codes, the diagnostic procedures for all of them will be the same.


The symptoms of a P2138 code might include stalling when you come to a complete stop, absolute lack of power, no acceleration, rapid loss of power at cruise speeds, and a locked throttle at the present engine rpm, among others. In addition, the check engine light will illuminate, and a code will be assigned to indicate the problem.

Potential Causes of P2138 DTC

  • The wire connector or ‘pig tail’ on the throttle body, in my experience, frequently causes issues in the form of a weak connection. The female terminals on the pigtail get corroded or slide away from the connection, resulting in a short circuit. It is possible that a bare wire on the pigtail has shorted to ground. A distortion in the top cover of the throttle body prevented the gears from rotating properly. The electronic throttle body has developed a malfunction. The accelerator pedal sensor or its wiring did not function properly. The engine management computer has had a failure. In order to restore active responsiveness to the throttle body, the computer must be cycled through its relearn phase, or the computer must be reprogrammed by a dealer. The TPS sensors were not correlating for a few seconds.

Diagnostic / Repair Steps

Here are a few items to consider with the electronically controlled throttle. This system is more delicate and subject to damage than any other system, and it is also the most expensive. Treat it and all of its components with utmost caution. It only takes one spill or one harsh treatment to make it unusable. The throttle body contains all of the other components, with the exception of the sensor for the accelerator pedal. When you look closely at the throttle body, you will discover a flat plastic cover on the top of it.

The motor is equipped with a tiny metal gear that protrudes from the housing behind the cover.

The centering and supporting pin for the gear is inserted into the throttle body housing, while the top pin is inserted into the ‘thin’ plastic cover.

  • The first step is to go online and look for the TSBs (technical service bulletins) for your car that are related to the code you received. These Technical Service Bulletins (TSBs) are the outcome of consumer complaints or acknowledged defects, as well as the factory advised repair process. Consult an online service handbook or a computer repair manual for information on a possible relearn technique to reset the machine. For example, on a Nissan, start the engine and wait three seconds before continuing. Pushing and releasing the pedal five times in succession during the following 5 seconds will count as one rep. Ten seconds after pressing the pedal, release it and hold it for another seven seconds. Release the accelerator pedal when the check engine light begins to blink. Wait 10 seconds, then depress the pedal for another 10 seconds before releasing it. Remove the key from the ignition
  • Remove the electrical connector from the throttle body by pulling it out. Take a close look at it to see if there are any missing or twisted female terminals. Look for signs of corrosion. Using a little pocket screwdriver, remove any rust that has formed. Connect the wires by putting a little quantity of electrical lubricant on the terminals and reconnecting them. You may get a replacement ‘pigtail’ at most auto parts stores or from the dealer if the terminal connector has been twisted or has missing pins, and you should check the top cover of the throttle body for cracks or warping. If any are present, contact the vendor and inquire as to whether they offer only the top cover. n If this is the case, the throttle body should be replaced. Probe the accelerator pedal sensor with a voltmeter to determine its voltage. It will have a reference voltage of 5 volts and a changing signal adjacent to it. Start by turning the key in the ignition and carefully depressing the pedal. The voltage should gradually increase from.5 to 5.0 without interruption. If the voltage spikes or if there is no voltage at the signal wire, it should be replaced
  • Look online for the wire terminal identification on the throttle body of your car, which may be found on the throttle body. Check for power to the throttle motor by probing the throttle body connector. Helper should turn the key on and softly push the accelerator pedal. If there is no power available, the computer is at fault. If there is power, this indicates that the throttle body is faulty.
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Other DTCs associated with the throttle include: P0068, P0120, P0121, P0122, P0123, P0124, P0510, and more.

Related DTC Discussions

  • P2138 throttle/pedal positioning sensor switch d/e voltage correlation is a Nissan Titan code that appears in 2006. A p2138 error code was shown on my 2006 Nissan Titan, which had 128000 miles on it. I tried changing the throttle body, but nothing worked
  • I tried changing the acceleration pedal, but nothing worked
  • I hit a pothole while driving, and the engine light came on, giving me a p2138 throttle/pedal positioning sensor switch d/e voltage correlation
  • I tried changing the throttle body, but nothing worked. Code P2138 for the 2007 Grand Prix. Greetings to everyone. I have a 2007 Pontiac Grand Prix with a sunroof, and the vehicle is displaying the code P2138. Apparently, this has been going on for about a year now. When driving in heavy rain or extremely slick road conditions, the Reduced Engine Power warning will appear along with the check engine light on the dashboard. This only occurs when the da is wet, and never when the da is dry. Trailblazer P2135, P2138, P300, P303 (2004 model year) I’m experiencing some issues with my 2004 Trailblazer and am hoping that someone can put me in the correct route to resolve the situation. I’ve had the truck for nearly 2 years and have had no problems with it at all. It’s been a fantastic vehicle to drive. Approximately three weeks ago, I pulled out of the driveway and noticed a dash light that said ‘Reduced
  • 2018 Silverado DTC P2138 – Stranded three times so far.’ For the first time, I replaced the accelerator pedal with a sensor. The ECM was replaced for the second time. So, what do you do now? Is it necessary to replace the throttle body and its sensors? Is there anyone who can assist me?
  • P2138 decreased the number of engine difficulties My check engine light is illuminated, and it indicates that the engine power has been lowered. I adjusted the gas pedal because the codes said p2138. Is there anything else I need do after I’ve cleared the codes but before I start the vehicle? I’m aware that some cars must perform specific tasks in order to ensure that the environment is clear and safe before starting their vehicles. Thank you so much
  • Acura TL Error Codes from 2006 P0134 P2251 P2138 P0134 P0134 P0134 Acura TL (3.2) from 2006
  • There is no Sports Package with this vehicle. I was having some automotive issue
  • When I squeezed the gas pedal, my car barely moved at all. I took it to Auto Zone, and the codes that were displayed were as follows: Misconfiguration of the HO2S (B1) S1 Heather System, code P0134 (No Activity) Circuit with a high voltage sensor (P2251 A/F Sensor S1 V?r) Trailblazer p2138 code
  • P2138 application I have a 2005 Trailblazer with the numbers p0641, p2138, and p2135 on the dashboard. My accelerator pedal, throttle body, and new wires from the throttle body have all been replaced
  • Nonetheless, the vehicle is still in limp mode. Do you have any other suggestions? The following pilot 2005 numbers: P0137, P2138, P0300, P0302 through P0306 Hello, In the last few months, we’ve had a number of problems with our 2005 Honda Pilot. I went out and bought an OBD reader, and the following codes were shown (the majority of which were cylinder misfires): P0137 O2 Sensor Circuit Low Voltage Bank 1 Sensor 2 P0137 O2 Sensor Circuit Low Voltage P2138 Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation P2138 Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation Code P2138 on a 2009 Chevrolet Impala with the P03 code. My 2009 Chevrolet Impala suffered ‘traction control not functional’ for almost 1 mile, resulting in a significant loss of power. The ‘P2138’ code was stored when I shut off and restarted the engine, however it was cleared after around 50 miles. Everything has returned to normal. What am I supposed to do? What should the dealer do in this situation? This is an example of
  • P1125, P2138, and P2125 are the base model codes for the 2006 Pontiac Grand Prix. Hello, I’ve been experiencing problems with my 2006 Pontiac Grand Prix, which has been throwing the codes listed above. Even though I’ve rebuilt the throttle body and the pedal assembly, as well as discovered some exposed wires in the engine compartment (which I repaired), the problem continues to exist. Is there anything else that might be done to solve this?

Need more help with a p2138 code?

If you still need assistance with the P2138 error code, please ask your issue in one of our FREE vehicle repair discussion boards. Please keep in mind that this material is being provided solely for informational reasons. It is not meant to be used as repair advice, and we are not liable for any actions you take in relation to any vehicle. All of the information on this website is protected by intellectual property rights.

Reduced Power Mode? See here first

The following DTCs were received on 08-06-04-014: MIL/SES DTCs P060E, P1516, and/or P2135 and/or P2138 with reduced engine power: (Test and Charge Battery) – – – – – – – – – – – – – (Mar 4, 2008) Specifically, MIL/SES, DTCs P060E, P1516, and/or P2135 and/or P2138 with Reduced Engine Power are being discussed (Test and Charge Battery) Models from 2004 to 2007 Chevrolet Colorado (sometimes spelled Chevrolet Colorado) is a mid-size car manufactured by Chevrolet in the United States.

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GMC Canyon (model years 2004-2007) 2006-2007 HUMMER H3 is a three-wheeled vehicle.

When a technician examines the ECM, he or she may discover two or more of the DTCs listed below: P060E: Control Module Throttle Position (TP) System Performance (Control Module) P1516: Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance Throttle Actuator Position Performance Position of the throttle (P2135) (TP) Sensors 1-2 are used in this application.

  1. Correlation The reason for this is because a voltage drop in the battery during the cranking cycle may cause the codes to be set and the car to enter the decrease engine power mode.
  2. It is important to note that a low voltage condition may cause at least two of the following DTCs to be set.
  3. Refer to the Diagnostic System Check – Vehicle section in SI for further information.
  4. Consider whether there was a probable battery drain if the ignition voltage was low.
  5. Then, if the ignition voltage was sufficient when the code was set, carry out a standard SI diagnosis for the code or codes that were set.
  6. Okay, after further investigation, I discovered that the minimum battery voltage while cranking should be 5.23 volts; otherwise, you may experience the difficulties stated in this TSB.
  7. On 07-06-04-019, the vehicle experienced intermittent MIL/SES, DTC P2138, and reduced engine power (repair of the Instrument Panel (IP) to Body Harness Connector).
  8. Models: Chevrolet Passenger Cars and Light Duty Trucks from 2005 to 2008.
  9. Customer feedback on an intermittent MIL/SES light illuminated with a message center or an indication that indicates Reduced Engine Power has been received from a small number of consumers.
  10. When the voltage difference between APP sensors 1 and 2 exceeds a preset value for more than 2 seconds, the sensor is considered to be malfunctioning.

Because the IP to body harness connector, which is responsible for carrying the APP signal to the ECM/PCM, is located in the left hand kick panel area of some vehicles and is not properly sealed, water can enter and cause a short in the APP circuits, which results in the P2138 code to be displayed on the dash display.

Locate the IP to body harness connector, which is likely to be at or near the left hand kick panel region of your vehicle.

Reduced Engine Power, MIL/SES Light, and DTCs P1516, P2135, and P2138 are all associated with the 07-06-04-003 code for the LSJ and L61 engines (Replace PCM) – – – – – – – – – – – – – (Jan 19, 2007) Reduced engine power, MIL/SES warning light, and DTC P1516, P2135 and P2138 are all associated with the LSJ and L61 engines (Replace PCM) The following Chevrolet Cobalt and Malibu models were produced in 2005-2006: Chevrolet Colorado and TrailBlazer from 2006 GMC Canyon and Envoy from 2006 HUMMER H3 (2006 model) Saturn ION, Saturn ION Red Line (2005-2006) Saab 9-7X with ECOTECTM technology was introduced in 2006.

2.0L or 2.2L I-4 Cylinder Engine (VINs P, F- RPOs LSJ, L61) or VORTECTM (VINs P, F- RPOs LSJ, L61) Engines with 2.8L I-4, 3.5L I-5, and 4.2L I-6 cylinders (VINs 8, 6, and S) ‘L52’ is an abbreviation for ‘L5.’ Customers who have returned for REPEAT repairs for DTCs P1516, P2135, and/or P2138 should only utilize the information in the accompanying notice.

This problem may recur, and upon further inquiry, the technician may discover the following DTCs set as current or in the previous history: DTC P1516 Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance Throttle Actuator Position Performance DTC P2135: Throttle Position Indication (TP) Correlation between sensors 1-2 DTC P2138 Position of the Accelerator Pedal (APP) Correlation between sensors 1-2 An internal problem with the PCM might be the source of this issue resulting in a repeat DTC of P1516, P2135, and/or P2138 being shown.

  1. Correction: It is critical that the APP sensor not be replaced.
  2. To identify whether or not the PCM will need to be changed in order to fix the repeat DTC P1516, an inspection of the PCM serial number year and Julian (PCM build) date will be required before following the diagnostic instructions in SI on DTCs P1516, P2135, and/or P2138.
  3. For further information on where to get the PCM serial number, see the graphic image (1) above.
  4. The ninth character represents the final digit of the year, while the Julian date is made up of the tenth, eleventh, and twelfth characters, and it is used to identify the day on which the PCM was built.
  5. If required, go to the Part Catalog to determine which PCM is appropriate for your vehicle’s use.

Vehicles having a PCM that was manufactured after the specified dates should consult SI diagnostics for DTCs P1516, P2135, and/or P2138. Just so you know, the APP sensor stands for Accelerator Pedal Position sensor.

07 Lmm P2138 Please Help!

The flow chart for the code is shown below. Using the scan tool APP sensor 1 parameter, check for a typical voltage range between 0.89 and 4.57 volts when the ignition is turned on. Using the scan tool APP sensor 2 parameter, check for a typical voltage range between 0.41-2.19 volts when the ignition is turned on. With the ignition turned on, compare the settings of the scan tool APP sensors 1 and 2. Examine them to ensure that they do not differ by more than 2 percent throughout a complete pedal sweep.

The DTCs P2122, P2123, P2127, P2128, and P2138 should not be set unless absolutely necessary.

Alternatively, you may choose to run the vehicle under the conditions that you noticed in the Freeze Frame Records data.

Allow for a minimum of 60 seconds for the ECM to shut down completely.

If the resistance is more than the prescribed range, check for an open or high resistance in the low reference circuit itself.

Testing should be done with the engine running and the ignition turned on.

If voltages are less than the specified range, check the affected 5-volt reference circuit for a short to ground or an open/high resistance.

If the value is more than the required range, check for a short to voltage in the affected 5-volt reference circuit.

In order to ensure that the scan tool APP sensor 1 and sensor 2 parameters are less than 0.02 volt, check the appropriate signal circuit terminals 2 and 5 for a short to voltage.

Install a 3A fused jumper wire between the signal circuit terminals 2 and 5 and the 5-volt reference circuit on each signal circuit.

If the value is less than the prescribed range, check the signal circuit for a short to ground or an open with a high resistance (if applicable).

Turn off the ignition and unplug the harness connector from the ECM.

The connection between the ECM C1 5-volt reference circuit terminal 38 and the APP terminal 3 is shown in Figure 1.

Check for infinite resistance between the APP sensor 1 and 2 signal circuits.

If all of the circuits pass the tests, the accelerator pedal assembly should be tested.

⇒ If the APP sensor passes all testing, the ECM should be replaced.

Test in a Dynamic Environment With the engine off, connect a 3-amp fused jumper wire between the 5-volt reference circuit terminal of the afflicted APP sensor and 5 volts while the ignition is turned off.

Install a jumper wire between the signal circuit terminal of the afflicted sensor and the ground terminal of the sensor.

Ideally, the voltage should range between 0.40 and 4.55 volts without any spikes or dropouts in the process. If the voltage does not fall within the prescribed range or is irregular, the APP sensor assembly should be replaced.

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