Pinpoint Test 1: The PCM Does Not Respond To The Scan Tool

PINPOINT TEST 1: THE PCM DOES NOT RESPOND TO THE SCAN TOOL

Normal Operation

The PCM communicates with the scan tool through the high speed controller area network (HS-CAN). Circuits (W/L) (HS-CAN +) and (W) (HS-CAN -) provide the network connection to the PCM. The PCM shares the HS-CAN network with the ABS module, the (4X4) control module, restraints control module (RCM), occupant classification sensor module (OCSM), power steering control module (PSCM) and the instrument cluster (IC). Voltage for the PCM is provided by circuits (GY/V) and (GY/R). Circuit (B) provides ground.

Possible Causes
- Fuse
- Wiring, terminals or connectors
- ABS module
- 4X4 control module (if equipped)
- IC
- PCM
- RCM
- PSCM
- OCSM

Diagnostic Procedure

CAUTION:Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE:Failure to disconnect the battery when instructed will result in false resistance readings. See - Service and Repair or - Service and Repair.
NOTE:Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the Pinpoint Test.

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