Diagnostic Symptom Guide

Symptom/Diagnosis - Antilock Brake System And Traction Control System:

Symptom/Diagnosis - Antilock Brake System Traction Control System:

Customers may comment that they hear the PMV assembly run at slow speeds (11 km/h 7 mph). This is simply the ABS system running through its self-test. It is also possible to feel the PMV assembly running through the brake pedal when it is barely applied, and to hear brake fluid return to the master cylinder. Also the vehicle may slowly decrease in speed while the PMV modulator valves increase fluid pressure to the wheel cylinders during this test. In both these instances, the driver must be traveling at a very low speed (11 km/h (7 mph) and have one foot touching the brake pedal (as some two-footed drivers may) to feel the PMV assembly running. These are normal conditions and in no way signify a problem with the ABS system.

When vehicle is equipped with traction control, any symptom which lights the ANTILOCK indicator also lights the TRACTION OFF indicator. Therefore, when both indicators are lit, follow ANTILOCK indicator diagnosis when no diagnostic trouble codes are set.

Vehicles with traction control contain a preventive system to avoid brake overheating. During heavy braking conditions, if a traction control mode is entered and the EBTCM determines the brakes are too hot, the EBTCM disables the traction control system and lights only the TRACTION OFF indicator. After a sufficient cooling time, approximately 15-20 minutes, the EBTCM enables traction control system and turns off the Indicator. This condition is normal and should not be mistaken as an intermittent system malfunction.