A few weeks after purchase, this Jeep just died while driving. None of the gauges would work, wouldn't crank, etc. Had PCM replaced and it worked fine for a bit. Then suddenly, it strands us in the middle of nowhere in the Bighorn Mountains of WY...and it acted just the same - died while driving, no gauges. Towed it home and took it to the shop that replaced the PCM. They said it was a bad 20a female mini fuse (Fuse 9 in the engine block fuse compartment). They replaced that and it ran fine. Then, driving across town, it died three more times each time we hit bumps in the road...and acted just like it did when the PCM failed. Each time it died, we replaced the female mini fuse (fuse 9) and we got home. In the driveway, each time my husband tried to start it, it would not turn over and the same fuse would blow. He played with some wires and found a bare starter wire, which he insulated. He also fixed a couple of other wire splices in the doors that had been done poorly by a previous owner. No PCM error codes. Drove it today and it was just fine. Just don't want to get stranded in the middle of nowhere again. Will definitely carry fuses...but does anyone have any ideas?
Jeep dies while driving after hitting bumps in road
- Thread starter horkim1
- Start date
Gunnersmate
TJ Enthusiast
There is a wiring harness that passes behind the valve cover and is routed around the threaded head stud on the drivers side.
The harness rubs on the threads and wears thru the split wire loom and the wiring insulation. The bare copper wires touch ground and you lose your gauge and sensor signals to/from the PCM.
This is a known problem on all years of TJs.
I installed a rubber insulator over the stud on my TJ so this will not happen.
The harness rubs on the threads and wears thru the split wire loom and the wiring insulation. The bare copper wires touch ground and you lose your gauge and sensor signals to/from the PCM.
This is a known problem on all years of TJs.
I installed a rubber insulator over the stud on my TJ so this will not happen.
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Rubicon88
TJ Addict
Fuse 9 powers the PCM and also the Automatic Shut Down Relay. If Fuse 9 blows, you will have the symptoms you describe above. The trick is finding what is causing the fuse to blow.
From fuse 9 there are two Red/Yellow wires....one goes to the PCM, connector C1, Pin 29. The other Red/Yellow wire goes to the Automatic Shut Down relay.
With the ignition on, the +12VDC from the Automatic Shut Down Relay is then connected to the PCM, connector C3, Pin 19, PCM connector C3, Pin 28, and to your ignition coil pack, fuel injectors and coil capacitor.
An intermittent short in any one of the power wires to these devices would cause Fuse 9 to blow and disable your Jeep.
From fuse 9 there are two Red/Yellow wires....one goes to the PCM, connector C1, Pin 29. The other Red/Yellow wire goes to the Automatic Shut Down relay.
With the ignition on, the +12VDC from the Automatic Shut Down Relay is then connected to the PCM, connector C3, Pin 19, PCM connector C3, Pin 28, and to your ignition coil pack, fuel injectors and coil capacitor.
An intermittent short in any one of the power wires to these devices would cause Fuse 9 to blow and disable your Jeep.
Gunnersmate
TJ Enthusiast
Thank you everyone for sharing your knowledge. We did check the ASD relay and it is good. Will trace the wires on the other circuits.
Rubicon88
TJ Addict
Your description is of something grounding itself out...bare hot wire hitting metal.
It could be very hidden and easily overlooked. It doesn't take much to short out a wire
Wow this is very good to know about. Is there a thread about this with pics? My 97 is definitely old enough that I could imagine this happening soon.
There have been several members that have posted pictures of the bare copper wires they found when the head bolt threads had rubbed thru the wire loom and insulation...
Here you go....
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Could have been the bare wire near the started that was hitting metal...which is now insulated
The picture shows where to look and the harness going around the stud.
You need to inspect the wire loom for abrasions....
Here's what I would do ... Let the Jeep idle and get everywhere and start wiggling wire bundles until it dies out, then you know which bundle the problem is in.
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