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thunder 01-20-2013 03:37 PM

Security light
Sorry i posted in a welcome center, I'm trying to learn this site. My problem is the security key light and MIL light stay on in Jeep. It starts and stalls in 3 seconds. Today I decided I would try a code reader. I tried reading and got no codes? decided to erase and started right up, gauges worked, fuel, tach, etc... Great ! Started 5-6 times perfect. Went to get changed so I could get gas and back to the same thing? Tried erase again to no avail. I have searched as much of wiring in doors as I can see. I know my drivers window motor is damaged but none of the windows or locks work from drivers door? The locks work on passenger door but no windows? I was so not hoping to go to dealer, but unsure now. Have not much respect for them around here. First one I called said come get key for $60, when I got there it jumped to $ 90 and $30 for programming. Then it was $120 and I have to tow Jeep there?
Any suggestions? I am pretty mechanically inclined, but electrically handicapped!

Frango100 01-21-2013 12:23 AM

Re: Security light
This seems to be a PCI data bus problem. The SKIM is communicating with the PCM via the PCI bus, to tell that a valid key is used. With the PCI bus down, this signal is not received and the engine starts and runs for a few seconds and shutts off. Due to the PCI bus down, the instrument cluster will light all lights, but instruments will not work, EVIC will show only dashes, power lock on drivers side will not work and an other bunch of things.
If your key was the problem, the engine would start and shutt down, but all other indications and systems would be ok.
Do you have an XJ, or WJ? Don't know the XJ, but for the WJ there is a diagnostic juntion port below the steering wheel, where all PCI wires come together and a shorting cap makes the connection between all. When you take the disconnect cap off, you isolate most of the systems, exept PCM, TCM and SKIM will still be connected together. Now you can start and see if the engine runs ok. The instrument cluster will not be working at this time, because its PCI bus is disconnected.
Since you have a problem with the drivers door motor, it could be that it locks up the drivers door module, which is connected to the PCI bus. Now you can connect each component via the diagnostic junction port to point 1 (which is connected to PCM/TCM/SKIM) and see if the problem returns. You could also measure the PCI bus voltage at the connector where you plug the scanner, it should be 0-2 Volts and fluctuating, showing the data signal. If its 0V all the time, a wire or a component is shorted. If its 4-7 V, a component has an internal failure and increases the bus voltage.
Also have a look at the following thread, where i posted some wiring schematics, which shows all components connected to the diagnostic junction port and also the position of this port.

thunder 02-03-2013 07:30 AM

Re: Security light
Thanks to all for help ! Found broken wires in door jamb: orange/white stripe, black. Fixed them. Another on main harness at headbolt rubbing. Unhooked window motor on drivers door, out of track and just plain broken. Put on new muffler to stop exhaust leaks. Bought code reader and put on new TP sensor.

All dash instruments working now. Dome and all work: dome, locks windows from driver door. Idles correctly and shifts right. All told about $100. Estimate from garage $1270.00. Glad I didn't do it.
Thanks again for all your help ! Jimmy

Frango100 02-03-2013 09:52 PM

Re: Security light
Nothing better then a cheap fix:D.

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