Test A: The Powertrain Control Module (PCM) Does Not Respond to The Diagnostic Tool
PINPOINT TEST A: THE POWERTRAIN CONTROL MODULE (PCM) DOES NOT RESPOND TO THE DIAGNOSTIC TOOLA1-A2:
Normal Operation
The PCM communicates with the diagnostic tool through the high speed CAN communications network, circuits 1908 (WH) and 1909 (BK). If one of the bus wires becomes shorted to ground or voltage, communications can continue at a reduced level. The PCM and instrument cluster share network termination responsibilities with the use of a split termination resistor in each module. If either of these termination resistors is lost, network communication is not possible. Check circuits 1908 (WH) and 1909 (BK) between the PCM C175b and the data link connector (DLC) C251. Total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open in one of the high speed CAN circuits, damage to the DLC C251, damage to the PCM C175b, or a problem in an in-line connector.
Possible Causes
- high speed CAN circuits 1908 (WH) and 1909 (BK) open
- DLC C251
- PCM C175b
- PCM
- instrument cluster
- PCM or instrument cluster termination resistors