Troubleshooting SKIM / PCM / no start

Jake kozlowski

Jake kozlowski

TJ Enthusiast
Joined
Feb 17, 2018
Messages
304
Location
Elmendorf Air Force Base, Anchorage, AK, USA
Recently was stranded off-road and something in the SKIM is the issue. Jeep just cranks and SKIM light stays illuminated.

2000 Jeep TJ, 2.5L, ax5

Steps I have taken;
Disconnect battery for 30 mins touching + and - together, reconnect, no start and light still on
Disconnect battery for 30 mins touching + and - together, disconnect SKIM module under dash, reconnect all, no start and light still on
Disconnect all connections going to PCM, clean, reconnect, no start and light still on
Lightly tapped dash, no start and light still on
Roughly smacked dash, no start and light still on

What other things need to be checked in the system? Will a code reader possibly show more information?

I have researched a few companies that flash your PCM and disable the SKIM module. Any recommendations?

Any and all help would be greatly appreciated!

Pic is from right before the issue... It was a long night of winching, and pulls!

FB_IMG_1574106915984.jpg
 
My light stays on for several seconds after start. My understanding is it doesn't search for your key side until the engine is running. If it doesn't detect the key side in under 5(?) seconds then it cuts the ignition and goes into lock down. This happens each time the engine starts.
So if my understanding of the system is right, then the skim may or may not be the (entire) problem.
 
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**UPDATE**
Attempted to hook up code reader. Code reader isnt recognizing the Jeep. Ive used this code reader on this Jeep many times and I tried it on my pick up and no issues.

If i leave the key in the on position, the odometer reads "no bus" and the only guage that moves is oil pressure and that just goes to zero.

I took apart the dash, cleaned and reconnected the instrument cluster. Still the same isssue.

I disconnected the CPS and no change.

Not sure what direction to go next. Any and all help would be greatly appreciated.
 
Jake kozlowski said:
**UPDATE**
Attempted to hook up code reader. Code reader isnt recognizing the Jeep. Ive used this code reader on this Jeep many times and I tried it on my pick up and no issues.

If i leave the key in the on position, the odometer reads "no bus" and the only guage that moves is oil pressure and that just goes to zero.

I took apart the dash, cleaned and reconnected the instrument cluster. Still the same isssue.

I disconnected the CPS and no change.

Not sure what direction to go next. Any and all help would be greatly appreciated.
Click to expand...

You may be able to send you're SKIM to Mark (@Wranglerfix) to test. I think that's where I would start is by testing the PCM and ruling it out.
 
Jake kozlowski said:
This is one of my first ever electrical issues I have ever had to deal with. It's a rough one for sure.
Click to expand...

I can imagine, I'm not even sure where you start with something like this. I suspect the FSM has a lot of info in it on diagnostics and troubleshooting.
 
Could be as simple as a bad ground or power cable. But then the oil pressure gauge shouldn't work either, you would think.
 
Well after lots of headache, it's running again!!

So, I had a bad wire from the back of the power distribution block (fuse panel under hood). The bad wire was rubbed which blew the add fuse, 30a, not the relay.

I found this out by inspecting the harness. Cut out the bad part and reconnected, but still no start. Tried swapping relays and no luck at all.

Plugged in a test light to the ecm connections. I had power at a2 but not a17. Another page said I need power at both. The same page said to jump power to the #30 connection of the add relay. I did that bam, no more problems. This means I'm not getting power from the asd fuse. The fuse looked great. Granted this isn't a normal fuse I'm used to checking. I pulled it out and it rattled!! So I put it back in and tapped it and saw it spark where it was broken.

So long story short, bad wire, bad fuse, whatever order.

Thanks for all the help!
 
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Thanks a million for the update.

More often than not, I think that situations like this are indeed related to bad wires / connections, so I'm not surprised. The trick is finding the bad wire, which can sometimes be daunting.

As far as that fuse goes, I've had that happen to me to, where a fuse looked like it was good, but there was a very, very small break in it.

Good detective work! Threads with happy endings are the best.
 
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Chris said:
Thanks a million for the update.

More often than not, I think that situations like this are indeed related to bad wires / connections, so I'm not surprised. The trick is finding the bad wire, which can sometimes be daunting.

As far as that fuse goes, I've had that happen to me to, where a fuse looked like it was good, but there was a very, very small break in it.

Good detective work! Threads with happy endings are the best.
Click to expand...
Lots of work for sure. I just got my mind set it was the cks. Which it wasn't, lol🤯
 
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Great job! Tunnel vision can be a troubleshooters worst nightmare. You need to understand the complete system and troubleshoot the entire thing for fastest results.
 
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