DTC P1600 - Serial Communication Problem Between Pcm & TCM
- Turn ignition on. Using a voltmeter, measure voltage (backprobe) between ground and PCM connector "C", terminal No. 2. If reading is about zero volts, go to next step. If reading changes between zero and 5 volts, check for an intermittent problem. See TESTS W/O CODES article. If reading is about 5 volts, check for poor connections or open Green/White wire between PCM and TCM. Repair as necessary. If wire and connections are okay, Replace TCM. Retest system.
- Turn ignition off. Disconnect TCM harness connector. Turn ignition on. Using a voltmeter, measure voltage between ground and terminal No. 17 (Green/White wire) at TCM. If reading is about 5 volts, check for an open TCM power or ground circuit. Repair as necessary. If circuits are okay, replace TCM. If reading is not as specified, check Green/White wire between PCM and TCM for poor connection or short to ground. Repair as necessary. If wire is okay, replace PCM. Retest system.