GM service bulletin #PIT4683F ABS wheel speed sensor codes? (Solution)

  • GM has issued a service bulletin #PIT4683F to provide additional testing instructions to diagnose and fix these trouble codes related to ABS wheel speed sensor issues on the vehicles listed below: C0035 C0040 C0045 C0050 C0245 P0609 Warning about testing active wheel speed sensors

What could cause a trouble code for one of the wheel speed sensors?

There are times when the magnets embedded within the bearing grease seal may cause a wheel speed sensor code, and in that case, the bearing must be replaced. Older wheel speed sensors are usually located outside the wheel hub.

How do you know if your ABS speed sensor is bad?

Five Common Signs of ABS Wheel Speed Sensor Failure

  1. Sign #1: The ABS Light Stays On.
  2. Sign #2: Traction and/or Stability Control is Disabled.
  3. Sign #3: It Takes Longer to Stop Your Vehicle.
  4. Sign #4: Your Vehicle Becomes Unstable During Braking.
  5. Sign #5: ABS Works Erratically.

What happens when a wheel speed sensor goes bad?

Failing wheel speed sensors will often result in the car turning off the traction control, the stability control, or other driver assist features.

Is a wheel speed sensor the same as a ABS sensor?

The ABS sensor is also called the wheel speed sensor or ABS brake sensor. Since all the wheels do not turn at the same speed, the ABS sensors report the speeds of all the four wheels to the ECM, based on which the ECM determines if the wheels are locking up.

Can ABS sensor cause transmission problems?

Occasionally, these sensors can fail or become faulty working intermittently sending inaccurate signals to the ECU. In your case it may be possible that the transmission is receiving a faulty signal from the ABS system.

What is code C0055?

Code C0055 stands for Rear Wheel Speed Sensor Circuit. The anti-lock brake system (ABS) prevents wheel lockup during emergency braking. This is accomplished by modulating brake pressure to the appropriate wheels. In essence, the ABS system ‘pumps’ the brakes in a panic stop.

What are the symptoms of a bad ABS module?

Signs Of A Faulty ABS Module

  • The ABS Warning Light Glows. This is the most common sign of problems with the ABS system.
  • The Brakes Lock Up. The ABS system is specifically designed to prevent any wheel from locking up during heavy braking.
  • An Unresponsive Brake Pedal.
  • Increased Pedal Effort.
  • Speedometer Failure.

Can you clean a wheel speed sensor?

With the sensor free, take your rag and wipe the sensor until it’s clean. I prefer not to use any chemicals on the sensor to avoid potential problems. If, however, the sensor is really grungy, use a mild soapy solution and rinse well. The ABS sensors are precision instruments in a crude environment.

What is code C0035?

Diagnostic trouble code (DTC) C0035 stands for “ Left Front Wheel Speed Sensor.” The C0035 is a generic chassis code that is set when the car’s anti-lock brake module perceives a fault with the left front wheel speed sensor or its circuit.

Will a speed sensor throw a code?

Its proper functioning depends on the data from the transmission speed sensors. If it fails to work, then it means the sensors have malfunctioned. The PCM will transmit an error code to ECU, which will shut down.

What happens if I disconnect ABS sensor?

On most vehicles, this is not an issue, but on some — notably pickup trucks — this can lead to lack of stability under heavy braking as the rear brakes lock up early. If unplugging the sensor makes your problem go away, don’t be fooled. Something in the ABS is making that wheel brake by itself, so get it fixed soon.

Are ABS sensors on all wheels?

Where are these sensors located? The ABS sensor is typically located in each wheel hub/rotor on a four channel ABS system. Some rear wheel drive applications have the sensor mounted in the rear differential.

GM service bulletin #PIT4683F ABS wheel speed sensor codes

A service bulletin, PIT4683F, has been released by General Motors to give further testing instructions for diagnosing and correcting various problem codes associated with ABS wheel speed sensor issues on the following vehicles: A0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

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Warning about testing active wheel speed sensors

The Electronic Brake Control Module is required to provide electricity to an active wheel speed sensor (EBCM). When checking the sensor, you may discover that the 12-volt supply voltage is not there, leading you to believe that the EBCM is malfunctioning. This is a common error. It’s possible that it isn’t. Whenever the EBCM determines that a wheel speed sensor is faulty, it purposefully TURNS OFF THE SUPPLY VOLTAGE TO THAT SENSOR. Do not confuse this characteristic with a poor EBCM.

Proper pre-testing technique for ABS wheel speed sensors

In most cases, if you have any of the following fault codes: C0035, P0609, C0040, C0045, C0050, C0245, or C0245P0609, it means that the EBCM has disconnected power to the wheel speed sensor. You must complete these activities before proceeding to the next level of testing. These procedures do not apply to General Motors vans or heavy-duty trucks. 1) Turn IGN off and remove the key from the ignition. Secondly, open and then close the driver’s door, and then wait for at least 60 seconds before continuing.

  • Then, with the probes of your multimeter set to DC volts and the range set to 40-60 volts, connect them to the EBCM’s supply voltage and signal circuits.
  • On the meter, you’ll observe a brief 12-volt pulse appear.
  • The integrity of the wheel speed sensor is checked using this power pulse.
  • 7.
  • If the harness passes all of the tests, inspect the terminals in the EBCM connector to ensure that none of the terminals are rusted or backed out of position.
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Next, test the active wheel speed sensors

Please be advised that this method is polarity sensitive. It is possible to harm the wheel speed sensor if the polarity is reversed. Connections: 1) With the IGN off, connect a 3A fused jumper from B+ to the Supply Voltage terminal of the wheel speed sensor. 2) Connect a jumper in series with a 100-ohm resistor to the negative terminal of the battery. 3) Set the DVOM to the milliamp scale for direct current.

4) As you gently turn the wheel, the reading should be between 4 and 8 milliamps for a low reading and 11 to 16 milliamps for a high reading (just a few degrees rotation at a time). 5) If the reading does not fall within the acceptable range, the wheel speed sensor should be replaced.

Vehicles affected by GM service bulletinPIT4683F

Buick Enclave from 2008 to 2013 Various Cadillac Escalade models from 2007 to 2013, as well as Escalade ESV and Escalade EXT models from 2009 to present. Chevrolet Avalanche, Silverado, Suburban, and Tahoe models from 2007 to 2013. Chevrolet Express from 2008 to 2012 Chevrolet Camaro (model years 2010–2013) Chevrolet Corvette and Traverse models from 2009 to 2013. Vehicles from 2007 to 2013 include the GMC Acadia, Sierra, Yukon, Yukon XL, Yukon Denali, Yukon Denali XL, and Yukon Denali XL. GMC Savana from 2008 until 2013.

Rick Muscoplat posted a blog entry on

2009 – 2013 Corvette: Service Bulletin: #PIT4683F: Additional Wheel Speed Sensor Diagnostics

Subject: Additional Wheel Speed Sensor Diagnostics
Models: 2008 – 2013 Buick Enclave
2007 – 2013 Cadillac Escalade, Escalade ESV, Escalade EXT 2009 Cadillac XLR
2007 – 2013 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2008 – 2012 Chevrolet Express
2010 – 2013 Chevrolet Camaro
2009 – 2013 Chevrolet Corvette, Traverse
2007 – 2013 GMC Acadia, Sierra, Yukon, Yukon XL, Yukon Denali, Yukon Denali XL
2008 – 2013 GMC Savana
2008 – 2009 Pontiac G8
2007 – 2010 Saturn Outlook
With any of the following DTCs: C0035 C0040 C0045 C0050 C0245 P0609

This PI has been replaced in order to reflect the most recent model and model year. PIT4683E should be discarded. If the vehicle displays the symptom(s) indicated in this PI, the following diagnosis may be of assistance to the driver. Condition/Concern: In the course of evaluating a wheel speed sensor issue, it is possible to discover that the 12 volt Wheel Speed Sensor Supply Voltage circuit from the EBCM is devoid of power. It is possible that this will result in the improper replacement of the EBCM due to the lack of power to the WSS.

Keep in mind that the only portion of this PI that relates to Vans or HD pickups is Step 2 under the Recommendation section.

  1. When a WSS fault is present, run the following tests to determine whether the ′′12 volt Wheel Speed Sensor Supply Voltage′′ from the EBCM is present. (This step is not applicable to Vans or HD pickup trucks.)
  • A. Disconnect the Tech 2 and Key Off Ignition, remove the key, open and close the driver’s door to turn off RAP (Retained Accessory Power), and wait at least 60 seconds
  • B. Disconnect the appropriate WSS harness connector
  • C. Disconnect the appropriate WSS harness connector
  • D. Disconnect the appropriate WSS harness connector
  • E. Disconnect the appropriate WSS harness connector
  • F. Disconnect the appropriate WSS harness connector
  • G. Disconnect the appropriate WSS harness connector
  • Using the appropriate test probes, connect the Fluke 87 DVOM (J39200) across the wheel speed sensor’s ‘Supply Voltage’ and ‘Signal’ circuits from the EBCM
  • D. Set the DVOM to DC volts, press the ‘range’ button to the 40 or 60 volt scale, and then press the ‘Min/Max’ button
  • E. Set the DVOM to DC volts, press the ‘range’ button to the 40 or E. Start the vehicle by turning the ignition key. When the EBCM is turned on, there will be a brief transitory 12 volt pulse from it. Each time the EBCM is switched on after being asleep, this 12 volt pulse is transmitted to check the integrity of the WSS circuit
  • F. If the 12 volt pulse is present, proceed with the WSS component testing. Prior to replacing the EBCM, double-check all of the circuits between the EBCM and the WSS to make sure that the 12 volt pulse is not missing. Using the appropriate Terminal Test Probes, check that there are no backed out or loose terminals at the EBCM, WSS, or any inline connections.
  • Testing the Wheel Speed Sensor as a separate component (Applies to All Models Listed) Please keep in mind that this technique is extremely polarity sensitive, and if the WSS is linked in reverse polarity while completing the procedures outlined below, the WSS may be irreversibly damaged. Note that the B+ signal should be tied into the WSS supply voltage, while the ground signal should be tied into the WSS low signal return (Fluke 87 DVOM). To calculate the WSS Supply Voltage and WSS Low Signal Return, see the appropriate SI wiring diagrams.
  • A. With the ignition turned off, disconnect the harness connector at the suspect wheel speed sensor
  • B. Connect a 3 amp fused jumper wire between Battery B+ and the ′′12 volt High Wheel Speed Sensor Supply Voltage′′ terminal
  • C. Connect a resistor of approximately 100 ohms in series with a Fluke 87 DVOM (J-39200) between the Battery Ground and the ′′Wheel Speed Sensor Low Signal Return′′ terminal
  • D. Disconnect the harness connector at [High Speed GM Lan terminating resistor, various test lights, Radio Shack, and other sources of a 100 ohm resistor are examples of such sources]. The illustration below demonstrates how to correctly connect your meter for testing purposes. D. Change the scale on the DVOM to the DC Milliamp scale. E. The normal value for the ′′Low′′ reading will be 4 to 8 mA, while the typical reading for the ′′High′′ reading will be 11 to 16 mA. F. If the signal does not fall within the prescribed range when the wheel is spun very slowly, a few degrees at a time, the wheel speed sensor should be replaced.
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Please carefully follow the steps in this diagnostic or repair procedure and finish each step. It is not necessary to complete the remaining stages if the condition indicated is resolved without completing all of the measures listed above.

Stabilitrack and ABS lights on, service bulletin

Each wheel bearing includes a built-in speed sensor that measures the rotational speed of the wheel. The sensor is comprised of an electromagnet that is fixed in place. It’s possible to think of the ring with teeth as being on the hub side of the bearing, but that’s not what it is. similar to a gear The speed sensor and the accelerometer are the two components. When the vehicle is in motion, the electromagnet is activated, and the trigger wheel (gear) rotates in sync with the vehicle wheel to provide a smooth operation.

  • The computer is pleased that it is transmitting and receiving signals as long as the wheel speeds are the same, plus or minus a pre-established range of values.
  • and occasionally there is an excessive amount of it accumulated.
  • The information that the computer is receiving is incorrect.
  • When the ignition is switched off, most of the metallic particles that have collected fall to the ground.

However, as can be seen, there are situations when a little amount hangs on. There isn’t much that the consumer can do to avoid this. Usually, a simple cleaning and blow-off with compressed air of the electro magnet (also known as a stator) would take care of the problem. Rob

The Most Common Problems With Traction Control

A speed sensor is integrated into each wheel bearing. An electromagnet is used as a sensor, and it is permanently fixed. It’s possible to think of the ring with teeth as being on the hub side of the bearing, but that’s a misnomer. the same as a transmission The speed sensor and the temperature sensor are the two components. When the vehicle is in motion, the electromagnet is energized, and the trigger wheel (gear) rotates in sync with the vehicle wheel to provide a more accurate response. As each ‘tooth’ travels through the electromagnet, the ABS computer receives a return signal variation caused by the closeness of each tooth traveling through the magnet.

  1. To summarize, the metallic brake dust is attracted to the electromagnet, which is a bunch of gobbledegook.
  2. This causes interference with the signal, which is what causes the ABS/TRACTION CONTROL lamp to illuminate and turn on the vehicle.
  3. All automobiles have the potential to be affected by this issue, although only a small number of them are.
  4. The fact that a little amount lingers in there may be seen, though.
  5. Typically, a simple cleaning and blow-off with compressed air of the electro magnet (also known as a stator, by the way) would cure the problem.

A Sensitive System

Despite the fact that traction control has several advantages, it can be a nuisance in some situations, such as when approaching or exiting a parking area with rutted snow. Some systems are so sensitive that they limit power or apply the brakes to such an extent that you are unable to move forward at the slightest hint of wheel slide. Fortunately, most cars have the option of turning off their traction control systems, allowing you to use the time-tested approach of rocking your vehicle back and forth to push your way out of the snow if necessary.

Dirt, Grime, and Debris

Sometimes the warning light will illuminate because the wheel-speed sensors are coated with road filth or debris, which causes the warning light to illuminate. It is possible for the wheel-speed sensors, wiring, connections, control module, and other components to experience intermittent issues or entirely fail. The sensors, cables, and connections, in particular, are positioned at each wheel, making them particularly vulnerable to failure. They are subjected to a hammering from potholes, water, snow, mud, asphalt, stones, and other debris, among other things, making them prone to failure.

Several General Motors vehicles from recent years have experienced sensor failures due to debris, prompting GM to send a technical service bulletin to dealerships in order to resolve the issue.

Faulty Wheel-Speed Sensors

Sensors that measure wheel speed are meant to detect when one of the vehicle’s drive wheels is spinning faster than the others, indicating that the vehicle is losing grip or slipping. The system will subsequently reduce power to that wheel and/or apply the brakes to that wheel as a result of this. When the spinning wheel is stopped, the power can be transferred to the other driving wheel or wheels that have higher traction on the road. (It is because of this concept that ABS-based traction control has been able to take the role of limited-slip differentials in some cars, which perform the same purpose.) When the traction control system is turned off, you’ll have to deal with tire slippage the old-fashioned way: by removing your foot off the gas pedal.

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What to Look For

When there is an issue with the system, a dashboard warning light, such as the one seen above, will typically glow on a constant basis, signaling that traction control has been turned off. Keep in mind that the brief lighting of the warning light is typically not a cause for concern. As soon as you turn on the ignition, the light should illuminate briefly for a few of seconds. It should also illuminate when the system recognizes that a wheel is rotating freely and performs its function to increase traction.

The problem code that caused the warning light is often read using a scanning instrument, which is typically used for diagnosis.

While traction control is a critical safety component, it is not always necessary to replace it as quickly as a malfunctioning ABS or stability control system.

The difficulty begins as soon as it begins to rain or snow; once you begin driving on wet or slippery terrain, it becomes more difficult to maintain control of the vehicle while accelerating.

At V F

If you find that your traction control light is illuminated, please come in as soon as possible to see us. It is our goal to assist you in diagnosing the problem, making the required repairs, and taking steps to prevent it from occurring again. Our vehicle repair services are also backed by an industry-leading 3 year/36,000 mile guarantee on both parts and labor! Call us at (413) 314-2280 or use our online scheduling tool to arrange an appointment now.

Any Chance I Can Get A Hold of This TSB

On the 08-05-25-004A, the Antilock Brake System (ABS), the Traction Control System (TCS), or the StabiliTrak light is illuminated, and the DTCs C0035-C0052 are stored (Perform Diagnostic Component Test Procedure and Repair as Necessary) – – – – – – – – – – – – – (Oct 27, 2008) When the ABS, Traction Control System (TCS), or StabiliTrak light is illuminated, and the DTCs C0035-C0052 are set, the subject is ABS, Traction Control System (TCS), or StabiliTrak light is illuminated (Perform Diagnostic Component Test Procedure and Repair as Necessary) Models:2007 Terraza is a Buick model.

Buick Allure, LaCrosse, and Lucerne models from 2007 to 2009.

Pontiac Grand Prix during the 2007-2008 season Cadillac Escalade SV6 2007-2009 Pontiac Montana 2007 Saturn Relay Models are being added to this bulletin as it is being updated.

-Condition Some consumers may notice that the warning lights for the Antilock Brake System (ABS), Traction Control System (TCS), or StabiliTrak (if installed) are activated, and they may express concern.

DTCLocation Circuit for the left front wheel speed sensor (C0035) C0036Range and performance of the left front wheel speed sensor circuit C0037Low voltage on the left front wheel speed sensor circuit Circuit for the right front wheel speed sensor (C0040).

Low speed sensor circuit for the right front wheel on the C0042.

Do not replace the EBCM or any other component(s) until the problem has been identified.

Continue to the Circuit/System Testing section of the appropriate Diagnostic Information and Procedures manual for the vehicle you are currently working on if the root cause cannot be identified.

Remove the harness connector at the appropriate wheel speed sensor while turning off your vehicle’s ignition system.

Measure the resistance between the signal terminal A and the low reference signal terminal B between 850 and 1350 ohms.

If the wheel speed sensor does not operate within the prescribed range, it should be replaced.

Check for infinite resistance between each terminal and the steering knuckle using a resistance meter.

If the reading is less than the prescribed value, the corresponding wheel speed sensor should be replaced.

Rotate the wheel while keeping an eye on the voltage difference between the signal terminal A and the low reference terminal B.

If the wheel speed sensor’s range is less than the specified range, it should be replaced. Information Regarding Warranties When repairing cars under warranty, apply the specified labor code for the bearing and hub assembly that is appropriate.

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