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Derrick, ASE Certified Technician
Category: Jeep
Satisfied Customers: 923
Experience:  A.S.-Automotive Analysis A6-Electrical A8/L1-Engine Performance Cert., CA Chrysler/Jeep/Dodge Tech
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My 1999 cherokee sport [XJ] is having ignition / starting problems.

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My 1999 cherokee sport [XJ] is having ignition / starting problems. When I try to start the key lock symbol appears in the dash read out, and the car wont start. Turns over a treat but wont fire. Have been told by a jeep dealer that the problem is the key reader,or skimmer does not recognise the key,and wont allow the fuel pump to work,, no fuel ,nostart. So,, we replace the ignition barrel,and the skimmer,and the key,,reprogramme them all,and things go well, for about 5/6 starts, then nothing again. Problem however is intermittent,,,.. So,, is/was the initial diagnosis wrong, and if so ,what might I do to fix it??? HELP PLEASE, if possible..

Hi there,


The way this system operates is like this. When you put your key in the ignition, the SKIM (Security Key Ignition Module) recognizes it and tells the PCM (Powertrain Control Module) to allow the car to start. Otherwise the car will not start.


I would like to backtrack to verify what has been performed here. You stated the SKIM was replaced, was it a used one or new one, and was it properly programmed to the PCM?

Was the new key a SKIM key (a SKIM key is gray, not black), and was it programmed to the SKIM module?

Was all of this performed at a dealership or any of it at a private shop or individually?

Has the PCM been replaced?


Sorry for all of the questions, but this will help me narrow down your problem.


Thank you,


Customer: replied 6 years ago.

Hi Derrick,


Answers as best I can - 1) the SKIM key is new 2) a programme procedure took place, but I don't know if it was correctly done - but 3) it was done at a Jeep dealership, 4) I have no knowledge of a PCM. I would say "no" it wasn't replaced, because it is not on my invoice.

THe invoice is showing a replaced ignition barrel and SKIM module, and new, grey, key.

Thanks for your help,



Well this is a little tricky. If this was all done at a Jeep dealer, I will have to assume everything was done correctly and that a new SKIM was used. If the key is new, the SKIM is new, and everything was programmed correctly, then the only possibilities are a wiring problem between the PCM and the SKIM, or a bad PCM. I highly doubt the PCM to be the cause as I have never seen that happen. I would double check that nothing aftermarket is installed that may "tap" into the harness between these modules.


I would also verify with the dealership that the SKIM and SKIM key are new and properly programmed, as they will probably be questioning this the same way I am.


Let me know what you find!


Thank you,


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