TAC TIP: Wheel Speed Sensor Diagnosis
Wednesday August 19th, 2015

Wheel Speed Sensor Diagnosis

2007-2010 Saturn Outlook
2007-2014 GMC Acadia
2008-2014 Buick Enclave
2008-2014 Cadillac CTS/CTS-V
2009-2012 Chevrolet Colorado
2009-2012 GMC Canyon
2009-2014 Chevrolet Traverse
2010-2014 Buick LaCrosse
2010-2014 Cadillac CTS Wagon
2010-2014 Cadillac SRX (driven wheel bearings only)
2010-2014 Chevrolet Camaro
2010-2014 Chevrolet Equinox
2010-2014 GMC Terrain
2011-2014 Buick Regal
2011-2014 Cadillac CTS/CTS-V Coupe
2011-2014 Chevrolet Camaro Convertible
2011-2014 Chevrolet Cruze
2011-2014 Volt (2014 MY: front driven wheel bearings only)
2012-2014 Buick Verano (2014 MY: Front driven wheel bearings only)
2013-2014 Cadillac ATS-AWD/RWD (driven wheel bearings only)
2013-2014 Cadillac XTS
2013-2014 Chevrolet Malibu
2014 Cadillac CTS (VIN A including V-Sport)
2014 Chevrolet Impala (new body style)

An intermittent click or grind noise or ABS pump motor noises may be heard inside the vehicle at parking lot speeds and the ABS, Service Traction Control System, and/or Service StabiliTrak warning lamps may be on. DTCs C0035 (left-front corner), C0040 (right-front corner), C0045 (left-rear corner) or C0050 (right-rear corner) with symptom bytes 18, 5A, 0F may be set.

These conditions may be caused by single or multiple pieces of ferrous metallic debris stuck to the wheel speed sensor magnetic encoder ring. The magnetic encoder ring is part of the inboard bearing hub assembly. This does not apply to capped wheel bearings.

Vehicles equipped with electric power steering (RPO NJ2 only) may have a heavier steering feel at low speed and DTC U0415 may be set in the power steering control module. This is a normal default action with the loss of a wheel speed sensor signal.

Magnetic Encoder

Instead of a traditional mechanical type tooth tone wheel, some vehicles use a wheel speed sensor tone wheel 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 the magnetic encoder ring rotates and passes by the wheel speed sensor head, it generates a sine wave in the wheel speed sensor.

Cleaning the Ring

In most cases, cleaning any accumulated debris on the magnetic encoder ring will repair conditions related to DTCs C0035-C0050 with symptom bytes 18, 5A, 0F. The encoder ring is located on the inboard side of the bearing hub.

Do not use any type of magnetic tool to remove the debris from the bearing magnetic encoder; an external magnet can damage the encoder.

To properly clean the magnetic encoder ring, some applications may require removal of the bearing/hub assembly. Remove the foreign debris from the magnetic encoder ring by gently using a dry nylon soft bristle brush. Take care not to damage the bearing outer seal when brushing and/or cleaning the magnetic encoder debris. If debris still remains, wash the encoder ring using a mild soap detergent and wipe it dry.

After cleaning, refer to the appropriate service information and perform the vehicle diagnostic repair verification procedure for the set DTCs.

Magnetic Encoder Ring

Debris on the ring (1) before cleaning

Ring after cleaning

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