Test A: No Scan Tool Communication With Gem
NOTE:
After repair, clear Diagnostic Trouble Codes (DTC) and retest system.
- 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. Using NGS tester, observe Generic Electronic Module (GEM) PIDs IGN_A, IGN_R, IGN_S and IGN_O/L while turning ignition switch through all positions. If PID values agree with ignition switch positions, go to next step. If PID values do not agree with ignition switch positions, repair appropriate ignition switch circuit(s). See appropriate wiring diagram in POWER DISTRIBUTION article in WIRING DIAGRAMS.
- Turn ignition switch to LOCK position. Disconnect Central Junction Box (CJB) 34-pin harness connector C243. CJB is located under left side of instrument panel. Measure voltage between ground and CJB harness connector C243 terminal No. 11 (Tan/Black wire). See Fig 1 . If more than 10 volts exists, go to next step. If 10 volts or less exists, repair open in Tan/Black wire.
- Disconnect GEM from CJB 18-pin harness connector C267. Connect CJB harness connector C243. Measure voltage between ground and CJB harness connector C267 terminal No. 4 (component side). Measure voltage between ground and CJB connector C267 terminals No. 16. See Fig 1 . If more than 10 volts exists at both terminals, go to next step. If 10 volts or less exists at either terminal, replace CJB.
- Disconnect GEM 26-pin harness connector C239. Measure resistance between ground and GEM harness connector C239 terminal No. 26 (Black/Light Blue wire). See Fig 2 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in Black/Light Blue wire.
- Measure resistance between ground and GEM harness connector C239 terminal No. 14 (Black/Light Blue wire). If resistance is less than 5 ohms, repair module communications concern. See MODULE COMMUNICATIONS NETWORK - EXPEDITION & NAVIGATOR article. If resistance is 5 ohms or more, repair open or high resistance in Black/Light Blue wire.