Test J: No Scan Tool Communication With Gem
WARNING: This page is about a different car, the 2000 Mercury Mountaineer, 2000 Ford Explorer, 1999 Mercury Mountaineer, and 1999 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
After all repairs, clear DTCs and retest system.
- Check battery junction box maxi-fuse No. 1 (50-amp). If fuse is okay, go to next step. If fuse is not okay, replace fuse. Clear DTCs and retest system. If fuse fails again, check for short to power in Tan/Black wire between battery junction box and fuse junction panel. Repair circuit as necessary.
- Check fuse junction panel fuse No. 25 (7.5-amp). If fuse is okay, go to next step. If fuse is not okay, replace fuse. Clear DTCs and retest system operation. If fuse fails again, check for short to ground White/Yellow wire between fuse junction panel and GEM. Repair circuit as necessary.
- Measure voltage between fuse junction panel fuse No. 25 (7.5-amp) fuse holder (input side) and ground. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair Tan/Black wire. See POWER DISTRIBUTION article in WIRING DIAGRAMS.
- Turn ignition off. Disconnect negative battery terminal. Disconnect GEM 18-pin connector C283. Connect negative battery cable. Measure voltage between GEM connector C283 terminal No. 11 (White/Yellow wire) and ground. See Figure . If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair White/Yellow wire between fuse junction panel and GEM.
- Turn ignition off. Disconnect negative battery terminal. Disconnect GEM 26-pin connector C280. Connect negative battery cable. Measure resistance between GEM connector C280 terminal No. 14 (Black/White wire) and ground. See Fig 1 . Measure resistance between terminal No. 26 (Black/White wire) and ground. If each resistance is less than 5 ohms, go to next step. If either resistance is 5 ohms or more, repair open in appropriate Black/White wire(s) between GEM connector C280 and ground. Ground point is located left front engine compartment near radiator.
- Measure resistance between GEM 18-pin connector C283 (Black wire) terminal No. 18 and ground. See Figure . If resistance is less than 5 ohms, problem is in module communications network. See MODULE COMMUNICATIONS NETWORK - EXPLORER & MOUNTAINEER article. If resistance is 5 ohms or more, repair open in Black wire.