ABS - With Commercial Chassis

CIRCUIT DESCRIPTION
The PCM monitors various parameters and will not allow Traction Control operation if any parameter falls beyond a predetermined value.

CONDITION FOR SETTING THE DTC
A malfunction has been detected by the PCM. The PCM then causes TCS shutdown until the malfunction has been corrected.

ACTION TAKEN WHEN THE DTC SETS
This is a temporary operational malfunction. A malfunction DTC is stored, TCS is disabled and the TRACTION CONTROL indicator lamp is turned ON. ABS remains functional. If TCS is no longer inhibited the indicator lamp will be turned OFF but the DTC will still be stored.

CONDITIONS FOR CLEARING THE DTC
Condition for DTC is no longer present and scan tool clear DTC function is used. Fifty start cycles have passed with no DTCs detected.

DIAGNOSTIC AIDS
This code is for information only. It indicates there are no problems in the ABS/TCS system, as an aid to the technician.

TEST DESCRIPTION
The numbers below refer to step numbers on the diagnostic table.
4. Checks if DTC C1278 resets.