Power control module

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Joey D

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I have some issues on my 06 limited. Scanner gives transmission control low voltage code, engine light comes on then driving for a while during a good rain it goes out comes back on after a few days. Some weird vibration comes and goes, sometimes, along with that. I bought a used PCM from a seller on ebay. Salvage yard I think but don't know. They did ask for VIN, Mileage, existing PCM p/n. I'm wondering is there any risk to swapping the ebay one with my current one? Anything I need to be aware of? I doubt there would be any risk but am looking for any tips etc.
 

Johnny O

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What code is the MIL throwing? (Check engine light)

Also, how are your ground straps looking?
 

tommudd

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If you bought a used one you are taking chances on it
A remanned one is not that expensive and they will set it up for your rig and it's plug and play
Otherwise trip to dealer
 

Billwill

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I agree with LabRat that the grounding straps should be checked!

The two straps at the rear of the heads going to the Firewall are the main suspects but the grounding of the PCM is also important and the Battery grounding to engine/chassis.

If you do not already have the 2006 KJ Service Manual then download it here...section 8W has the Wiring Diagrams and the Index there will direct you to all the Ground points!

A new PCM will have to have the SKEES data programmed into it!;)

www.colorado4wheel.com/manuals/Jeep/KJ/
 
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Johnny O

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I agree with LabRat that the grounding straps should be checked!

The two straps at the rear of the heads going to the Firewall are the main suspects but the grounding of the PCM is also important and the Battery grounding to engine/chassis.

If you do not already have the 2006 KJ Service Manual then download it here...section 8W has the Wiring Diagrams and the Index there will direct you to all the Ground points!

A new PCM will have to have the SKEES data programmed into it!;)

www.colorado4wheel.com/manuals/Jeep/KJ/
Agreed. I’m by no means a Jeep expert, but in my experience weird intermittent electrical faults are often traced back to either bad ground connections or pinched/kinked/missing insulation on wiring.

once I fixed an intermittent CanBus fault on a flexofolder printer others had chased for years when I determined the copper core wire was broken inside the insulation at a flex point. Machine worked great when open, but would fail randomly when closed as the bend seperated the two bits of the conductor.

I can’t count how many intermittent faults like the OP describes have been corrected by replacing damaged ground straps or their tightening/cleaning connection hardware.

an easy way to troubleshoot these is to take a peice of Large gauge multi strand wire and use it as a jumper over the suspected ground. Jumper the ground from connecting point to connecting point and see if you fault goes away. Just remember to only do one at a time.

in this case, as @Billwill states id visual inspect those under the hood, but I’d use the jumper method for those on the undercarriage engine and transmission.

another thing I would check is all fuses and relays. With the battery disconnected, make sure everything is seated properly in its sockets.

PLEASE remember that one should never work only any automotive electrical with the battery connected as this is a sure fire way to “prove” your brain box let the smoke out. (Fellow twidgets excluded of course…)
 

Billwill

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Totally agree with the above advise escpecialy as regards adding extra grounds to jumper over existing grounds!
You can never have too many grounds except in Audio installations!;)

Also disconnecting the Battery completely when diagnosing suspect wiring.....except if you are tracing a bad connector or suspect wire then you have no choice but to carefully work through the wiring as per the Wiring Diagrams. In these cases I ground my Multimeter with one lead then probe the suspect wiring by carefully piercing the wire's insulation with a sharp pin or needle attached to the other Multimeter lead....then dab some glue over the pinprick hole when finished.;)

I have pulled off about 15 bad wiring issues on my 2002 CRD after a frontal impact....have not had a problem for more than a year now.... touch wood!:rolleyes:
 

Johnny O

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Totally agree with the above advise escpecialy as regards adding extra grounds to jumper over existing grounds!
You can never have too many grounds except in Audio installations!;)

Also disconnecting the Battery completely when diagnosing suspect wiring.....except if you are tracing a bad connector or suspect wire then you have no choice but to carefully work through the wiring as per the Wiring Diagrams. In these cases I ground my Multimeter with one lead then probe the suspect wiring by carefully piercing the wire's insulation with a sharp pin or needle attached to the other Multimeter lead....then dab some glue over the pinprick hole when finished.;)

I have pulled off about 15 bad wiring issues on my 2002 CRD after a frontal impact....have not had a problem for more than a year now.... touch wood!:rolleyes:
Aye! I dub the “twidget”!
 
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