C1278

Diagnostic Chart - Part 1 Of 2:

Diagnostic Chart - Part 2 Of 2:

Electrical Schematic:

CIRCUIT DESCRIPTION
When excessive wheel spin is detected by the Electronic Brake/Traction Control Module (EBCM/EBTCM), it will request the PCM to reduce engine torque via a high speed pulse width modulated (PWM) signal on circuit 463.

CONDITIONS FOR SETTING THE DTC
If PCM codes are present, the malfunction may not exist with the ABS/TCS system. Refer first to Powertrain Management / Computers and Control Systems / System Diagnosis.

DTC C1278 sets when the EBTCM receives a communication failure data message from the PCM. DTC C1278 sets under the following two conditions:
1. EBTCM to PCM communications. CKT 463 or CKT 800 open or shorted.
2. PCM driveability conditions that would set a PCM code(s).

ACTION TAKEN WHEN THE DTC SETS
A malfunction DTC is stored, TCS is disabled and the TRACTION OFF indicator lamp is turned ON.

CONDITIONS FOR CLEARING THE DTC
^ Conditions for the malfunction are no longer present and scan tool clear DTCs function is used.
^ 100 ignition switch key cycles have passed with no malfunctions detected.

DIAGNOSTIC AIDS
It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully inspect wiring may result in misdiagnosis, causing part replacement with reappearance of the malfunction.

A thorough inspection of grounds G101, G102, G106, and G110 should be performed.