FCM, PCM Communication Fault
NOTE:
After making any repairs, perform BODY VERIFICATION TEST under VERIFICATION TESTS.
- Turn ignition on. Using scan tool, select INSTRUMENT CLUSTER, SYSTEM TESTS then PCM MONITOR. If scan tool does not display PCM IS ACTIVE ON BUS, go to next step. If scan tool displays PCM IS ACTIVE ON BUS, erase DTCs. Turn ignition off and back on. Wait a minimum of one minute. Recheck for DTCs. If DTC does not reset, test is complete. If DTC resets, replace Front Control Module (FCM). See FRONT CONTROL MODULE under REMOVAL & INSTALLATION.
- Using scan tool, attempt to communicate with Powertrain Control Module (PCM). If scan tool communicates with PCM, go to next step. If scan tool does not communicate with PCM, go to NO RESPONSE FROM PCM (PCI BUS) .
- Turn ignition off. Disconnect scan tool from Data Link Connector (DLC). Locate and disconnect PCM connectors. See COMPONENT LOCATIONS . Connect Diagnostic Junction Port Tester (8339) to diagnostic junction port. See COMPONENT LOCATIONS . Using DVOM, measure resistance of White/Violet wire between PCM connector C2 terminal No. 59 and diagnostic junction port terminal No. 1. See Fig 2 and Figure . If resistance is 5 ohms or less, replace PCM. See POWERTRAIN CONTROL MODULE under REMOVAL & INSTALLATION. If resistance is greater than 5 ohms, repair open in White/Violet wire.