DTC 78

DTC 78 PCM Detected Communication Malfunction:

CIRCUIT OPERATION
When excessive wheel spin is detected by the EBTCM, it will request the PCM to reduce engine torque via a high speed pulse width modulated (PWM) signal on circuit 463.

FAILURE CONDITIONS
Important
^ If PCM codes are present, fault may not exist with the ABS/TCS system.

DTC 78 sets when the EBTCM receives a communication failure data message from the PCM. DTC 78 sets under the following two conditions.

1. EBTCM to PCM communications.
^ CKT463 or CKT 800 open or shorted.
2. PCM driveability conditions that would set a PCM code(s).
^ It is very important that a thorough inspection of the wiring and connectors be performed.

Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.