Test H: The Powertrain Control Module (PCM) Does Not Respond To The Diagnostic Tool

PINPOINT TEST H: THE POWERTRAIN CONTROL MODULE (PCM) DOES NOT RESPOND TO THE DIAGNOSTIC TOOL

H1-H3:

Normal Operation
The PCM communicates with the diagnostic tool through the controller area network (CAN) circuits 4-EC7 (GY/RD) and 5-EC7 (BU/RD). If one of the CAN communications network circuits become shorted to ground or voltage, or if some but not all termination resistors are lost, communications can continue. Check circuits 4-EC7 (GY/RD) and 5-EC7 (BU/RD) between the PCM C175b and the data link connector (DLC) C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open in circuit 4-EC7 (GY/RD) or 5-EC7 (BU/RD), damage to the DLC C251, or damage to the PCM C175b.

Possible Causes
- CAN data plus circuit 4-EC7 (GY/RD) open
- CAN data minus circuit 5-EC7 (BU/RD) open
- PCM C175b
- PCM