Test B: No Communication With Generic Electronic Module
WARNING: This page is about a different car, the 2002 Lincoln Navigator and 2002 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
After making any repairs, clear DTCs and perform self-test.
- Turn ignition switch to LOCK position. Connect New Generation Star (NGS) tester to Data Link Connector (DLC). DLC is located below center of instrument panel, right of steering column. On manual transmission models, depress clutch pedal while testing ignition switch. Observe GEM 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 ignition switch positions, repair appropriate ignition switch circuit(s). See POWER DISTRIBUTION in appropriate SYSTEM WIRING DIAGRAMS article ELECTRICAL.
- Turn ignition switch to LOCK position. Disconnect central junction box 34-pin harness connector C243. Central junction box is located under left side of instrument cluster. Measure voltage between ground and central junction box harness connector C243 terminal No. 11 (Tan/Black wire). See Fig 1. If battery voltage exists, go to next step. If battery voltage does not exist, repair open in Tan/Black wire between battery junction box and central junction box. See POWER DISTRIBUTION in appropriate SYSTEM WIRING DIAGRAMS article ELECTRICAL.
- Remove GEM from central junction box connector C267. Central junction box is located under left side of instrument cluster. See GENERIC ELECTRONIC MODULE under REMOVAL & INSTALLATION. Reconnect central junction box harness connector C243. Measure voltage between ground and central junction box connector C267 terminal No. 4 (component side). Measure voltage between ground and central junction box connector C267 terminal No. 16 (component side). See Fig 1. If battery voltage exists at both terminals, go to next step. If battery voltage does not exist at either terminal, replace central junction box.
- Disconnect central junction box harness connector C243. Central junction box is located under left side of instrument cluster. Measure resistance between terminal No. 11 at connector C243 and terminal No. 4 at connector C267 of central junction box (both at component side). Measure resistance between terminal No. 11 at connector C243 and terminal No. 16 at connector C267 of central junction box (both at component side). See Fig 1. If resistance is 5 ohms or less between all terminals, go to next step. If any resistance is more than 5 ohms, replace central junction box.
- Disconnect GEM 26-pin Gray harness connector C239. GEM is located on back side of central junction box. Measure resistance between ground and GEM harness connector C239 terminal No. 26 (Black/Light Blue wire). See Fig 2. If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, repair open in Black/Light Blue wire between GEM and ground. Ground point is located behind left kick panel.
- Measure resistance between ground and GEM 26-pin harness connector C239 terminal No. 14 (Black/Light Blue wire). If resistance is 5 ohms or less, problem is in module communications network. See MODULE COMMUNICATIONS NETWORK - EXPEDITION & NAVIGATOR article. If resistance is more than 5 ohms, repair open in Black/Light Blue wire between GEM and ground. Ground point is behind left kick panel.