Test B: No Communication With Generic Electronic Module/Central Timer Module (Gem/CTM)
NOTE:
After repair, clear DTCs and repeat self-test.
- Turn ignition switch to OFF position. Connect New Generation Star (NGS) tester to Data Link Connector (DLC). On manual transmission models, depress clutch pedal. Observe GEM/CTM PIDs IGN_A, IGN_S, IGN_O/L and IGN_R while turning ignition switch through all positions. If PID values agree with switch positions, go to next step. If PID values do not agree with switch positions, repair appropriate ignition switch circuit(s). See POWER DISTRIBUTION article in WIRING DIAGRAMS.
- Turn ignition switch to OFF position. Disconnect central junction box connector C243. Measure voltage between central junction box connector C243 terminal No. 11 (Tan/Black wire) and ground. See Fig 1. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open or short to ground in Tan/Black wire between battery junction box and central junction box.
- Remove GEM/CTM from central junction box connector C267. See GENERIC ELECTRONIC MODULE/CENTRAL TIMER MODULE (GEM/CTM) under REMOVAL & INSTALLATION. Reconnect central junction box connector C243. Measure voltage between central junction box connector C267 terminal No. 4 (component side) and ground. Measure voltage between central junction box connector C267 terminal No. 16 (component side) and ground. See Fig 1. If each voltage is more than 10 volts, go to next step. If either voltage is 10 volts or less, replace central junction box.
- Disconnect central junction box connector C243. Measure internal resistance of central junction box between connector C243 terminal No. 11 (component side) and connector C267 terminal No. 4 (component side). Measure internal resistance of central junction box between connector C243 terminal No. 11 (component side) and connector C267 terminal No. 16 (component side). See Fig 1. If each resistance is less than 5 ohms, go to next step. If either resistance is 5 ohms or more, replace central junction box.
- Disconnect GEM/CTM 26-pin connector. Measure resistance between GEM/CTM 26-pin connector terminal No. 26 (Black/Light Blue wire) and ground. See Fig 2. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Light Blue ground wire. Ground point is located behind left kick panel.
- Measure resistance between GEM/CTM 26-pin connector terminal No. 14 (Black/Light Blue wire) and ground. If resistance is less than 5 ohms, problem is in module communications network. See appropriate MODULE COMMUNICATIONS NETWORK article. If resistance is 5 ohms or more, repair open in Black/Light Blue ground wire. Ground point is behind left kick panel.