Test U: No Communication With Generic Electronic Module
- Check condition of maxi-fuse No. 1 (60-amp) in engine compartment Battery Junction Box (BJB). If fuse is okay, go to next step. If fuse is blown, replace fuse. Clear DTCs and recheck system operation. If fuse fails again, check for short to ground in Tan/Black wire between BJB and Central Junction Box (CJB). Repair Tan/Black wire as necessary. Recheck system operation.
- Check fuse No. 25 (7.5-amp) in CJB. See Fig 1
. If fuse is okay, go to next step. If fuse is not okay, replace fuse. Clear DTCs and recheck system operation. If fuse fails again, check for short to ground in White/Yellow wire between CJB and GEM. Repair circuit as necessary. Recheck system operation.
- Measure voltage between ground and terminal No. 2 of fuse holder No. 25 (7.5-amp) in CJB. See Fig 1
. If more than 10 volts exist, go to next step. If 10 volts or less exist, repair open in Tan/Black wire. Clear DTCs and recheck system operation.
- Turn ignition switch to LOCK position. Disconnect GEM 18-pin harness connector C283. GEM is located behind center of instrument panel. Measure voltage between ground and GEM 18-pin harness connector C283 terminal No. 11 (White/Yellow wire). See Fig 2
. If more than 10 volts exist, go to next step. If 10 volts or less exist, repair White/Yellow wire between CJB and GEM. Clear DTCs and recheck system operation.
- Disconnect GEM 26-pin harness connector C280. Measure resistance between ground and GEM harness connector C280 terminal No. 14 (Black/White wire). See Fig 2
. If resistance is 5 ohms or more, repair open in Black/White wire between GEM and ground. Clear DTCs and recheck system operation. If resistance is less than 5 ohms, repair module communication concern. See MODULE COMMUNICATIONS NETWORK - EXPLORER & MOUNTAINEER article.
Courtesy of FORD MOTOR CO.
Courtesy of FORD MOTOR CO.