Rick's Free Auto Repair Advice

Service Traction Message

How to fix Service Traction Message or Service Stabilitrak Message

GM has issued a service bulletin #PIC5428G to address a Service Traction Message or Service Stabilitrak Message along with these possible trouble codes: C0035,  C0040,  C0045,  U0415, C0050. The bulletin applies to the vehicles listed below but does not apply to newer style wheel bearings that are capped.

If you notice the ABS, Service Traction Control System, Service Stabilitrak light(s) on and check for trouble codes and find any of these codes C0035,  C0040,  C0045,  U0415, C0050 this repair procedure may fix the problem. In addition to the lights and codes, you may notice that the steering feels “heavier” at low speeds or during parking maneuvers when the light(s) are on. You may also notice a brief  intermittent noise, click, ratchet, grind, or ABS pump motor noises typically heard from the inside of the vehicle at parking lot speeds.

GM has determined that the most likely cause of all these symptoms is metallic debris stuck to the wheel sensor portion of the wheel bearing hub. These wheel bearings operate by detecting the North/South poles of a magnetic ring. See the GM description of the new style bearing

“Some new model vehicles today have begun to use a different type of wheel speed sensor encoder ring or tone wheel. Instead of a traditional mechanical type tooth tone wheel, the wheel speed sensor tone wheel is now made of a magnetized nitrile rubber ring, typically brown in color. This magnetic encoder consists of multiple North and South pole pairs surrounding the outer circumference. When this magnetic encoder ring rotates and passes by the wheel speed sensor head; it generates a sine wave in the wheel speed sensor. The wheel speed sensor converts an analog signal to a digital square wave, and typical digital signal values switch between 7mA (Low) and 14mA (High) DC current.”

The ring is mounted on the inboard side of each wheel bearing and is exposed wheel bearingto the elements. However, on rear wheels of 2WD vehicles, GM may have used a “capped” wheel bearing that protects the magnetic ring from debris accumulation. The fix discussed in this bulletin does NOT apply to those capped wheel bearings. If you find a trouble code for a rear wheel that has a capped bearing, disregard this bulletin and follow the diagnostic procedures in the shop manual.

The magnetic can accumulate ring metallic debris from the road or during a brake rotor machining process. The ferrous debris causes the wheel speed sensor to miscount the magnetic poles and report a problem to the electronic brake control module (EBCM). The data from the wheel speed sensor is used to command the ABS brakes, stability control and traction control. When the EBCM sets any of the trouble codes mentioned above, the stabilitrack and ABS systems shut down and that also affects the electronic power steering.

Use the codes to determine which wheel speed sensor ring is causing the problem:

– C0035 Left Front Corner

– C0040 Right Front Corner

– C0045 Left Rear Corner

– C0050 Right Rear Corner

 

Models: 2008-2017 Buick Enclave

2010-2016 Buick LaCrosse

2011-2017 Buick Regal

2012-2017 Buick Verano (2014 MY: front driven wheel bearings only)

2013-2014 Cadillac ATS – AWD / RWD (driven wheel bearings only)

2014 Cadillac CTS (VIN A incl. V-Sport)

2008-2014 Cadillac CTS/CTS-V

2010-2014 Cadillac CTS Wagon

2010-2016 Cadillac SRX (driven wheel bearings only)

2013-2017 Cadillac XTS

2010-2015 Chevrolet Camaro

2011-2015 Chevrolet Camaro Convertible

2009-2012 Chevrolet Colorado

2011-2015 Chevrolet Cruze

2011- 2017 Chevrolet Volt (2014 MY: front driven wheel bearings only)

2010-2017 Chevrolet Equinox

2014-2017 Chevrolet Impala (New Body Style)

2013-2015 Chevrolet Malibu

2016 Chevrolet Malibu Limited

2009-2017 Chevrolet Traverse

2009-2012 GMC Canyon

2007-2016 GMC Acadia

2017 GMC Acadia Limited

2010-2017 GMC Terrain

2007-2010 Saturn Outlook

Clean wheel speed magnetic ring

To inspect the magnetic ring, shine a flashlight on the engine side of each wheel bearing. If you see metallic debris clinging to the rubber ring, remove the debris with a shop rag. Do NOT use a screwdriver or any other metal tool and do NOT use another magnetic to try and attract  the particles. GM advises to take care around the bearing outer seal when performing this cleaning operation.

GM also recommends brushing the magnetic ring with a nylon brush and using a mild soap detergent to fully clean the surface after removing the particles. On some applications you may have to remove the hub to gain access to the ring (nice going GM engineers!).

Clean trouble codes using a code reader or scan tool

Once you’ve removed the debris, clear the trouble codes and test drive the vehicle.

Do NOT replace the wheel bearing hub assembly before trying this procedure.

Posted on by Rick Muscoplat


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