Test A: No Communication With Generic Electronic Module
NOTE:
Before proceeding with this test ensure voltage exists at input side of fuse No. 39 (5-amp) in central junction box. Repair as necessary. See appropriate wiring diagram in POWER DISTRIBUTION article in WIRING DIAGRAMS.
- Turn ignition switch to LOCK position. Disconnect Generic Electronic Module (GEM) harness connector C291. Measure voltage at terminal No. 2 (White/Yellow wire) at GEM harness connector C291. See Fig 1 . If battery voltage exists, go to next step. If battery voltage does not exist, go to step 3 .
- Measure resistance between ground and terminal No. 4 (Black/White wire) at GEM harness connector C291. If resistance is 5 ohms or less, go to step 4 . If resistance is greater than 5 ohms, repair open in Black/White wire. See GROUND DISTRIBUTION article in WIRING DIAGRAMS.
- Remove fuse No. 39 (5-amp) from central junction box. Measure resistance in White/Yellow wire between terminal No. 2 at GEM harness connector C291 and output side of fuse No. 39. If resistance is 5 ohms or less, repair power distribution circuit as necessary. See appropriate wiring diagram in POWER DISTRIBUTION article in WIRING DIAGRAMS. If resistance is greater than 5 ohms, repair open in White/Yellow wire.
- Measure voltage at terminal No. 4 (Black/White wire) at GEM harness connector C291. If voltage exists, repair short to voltage in Black/White wire. If voltage does not exist, repair module communication concern. See MODULE COMMUNICATIONS NETWORK - MUSTANG article.