Service VME - ABS Wheel Speed Sensor Concerns

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

When diagnosing ABS wheel speed sensor codes, be sure that the wheel speed sensor air gap to the tone ring is correct before replacing a wheel speed sensor. As you are aware, a wide air gap will cause no sensor output or the sensor output to drop out. To reset the air gap, inspect the retainer for the sensor to insure it is in place and functioning. Push the sensor in against the tone ring. Drive the vehicle and observe the sensor output (note: Rotation of the wheels causes the air gap to be set to the proper distance). If it still is not functioning properly, continue following the diagnostic procedures.

While diagnosing wheel speed sensor output, you will notice that the wheel speed sensor readings on the Tech 2 do not match the speedometer reading. The problem is not with the ABS system. Do not replace ABS system components in an attempt to get the readings to match. The next release of the Tech 2 software will bring the readings closer together.

In either case, the diagnostic procedures in SI work well. Remember that you are looking for a difference in output between the four sensors or a dropout of one or more of the sensors, not whether the readings match the actual vehicle speed.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.