C0038

ABS/VSS & WSS Circuit Schematic:

CIRCUIT DESCRIPTION
As a toothed ring passes by the wheel speed sensor, changes in the electromagnetic field cause the wheel speed sensor to produce a sinusoidal (AC) voltage signal whose frequency and amplitude is proportional to wheel speed. The magnitude of this signal is directly related to wheel speed and the proximity of the wheel speed sensor to the toothed ring, often referred to as the air gap.

CONDITIONS FOR SETTING DTC
Any wheel speed differing from the vehicle speed for any of the following:
^ One mismatched wheel speed more than double or less than half the other 2 wheel speeds.
^ All four wheel speeds differing from each other by 8 percent.
^ Vehicle speed greater than 20 km/h (12 mph).
^ No unexpected wheel acceleration. Anything that generates consistent differences between wheel speed signals.

ACTION TAKEN WHEN THE DTC SETS
^ ANTILOCK indicator lamp is illuminated
^ ABS is disabled

NOTE: Diagnostic Trouble Code (DTC) C0038 is an ignition latched DTC which indicates the above is true until the ignition is turned to "OFF" (even if the cause of the DTC is intermittent).

CONDITIONS FOR CLEARING THE DTC
^ Conditions for setting the DTC are repaired and the Scan Tool clear (DTCs) function is used.

DIAGNOSTIC AIDS
A DTC C0038 is usually set by significantly different tires installed on the vehicle.

DTC C0038 Wheel Speed Signal Malfunction:

TEST DESCRIPTION
The number below refers to the step number on the chart.
[2] Check all speed sensor outputs using the Scan Tool.