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jironman 06-25-2014 09:14 AM

Alarm sounds when cranking - Jeep turns off
Hi guys,

New here & trying to read through to find info. But in the meantime any assistance would be greatly appreciated.

2004 Jeep GC Overland 4.7 HO

The vehicle alarm goes off when cranking the vehicle. It will stay on for a second or town then shut down. The only way I could stop the alarm was to disconnect the battery. I reconnected and tried the crank again. This time, no alarm but it wouldnt stay cranked. I also noticed the dash & overhead info gauges weren't working. The overhead info gauge is blank for everthing (direction, miles to empty, trip, etc.).

I've disconnected the battery for a bit. But no luck.

Any suggestions? Feel free to explain it to me like I'm a child. Thanks.

Frango100 06-25-2014 11:34 AM

Re: Alarm sounds when cranking - Jeep turns off
Welcome to the garage.
No instruments and no EVIC sounds as a dead PCI data bus. You could measure pin 2 of the data connector under the steering wheel, it should show 2.5 V more or less. If its 0 V, then the bus is shorted somewhere, if its around 7.5 V, then one of the components connected to the PCI data bus is faulty and is pulling the bus voltage up.
Does it still unlock/lock all doors with the remote, because the unlock signal to the drivers door goes from the passenger door module via the data bus to the drivers door module?

jironman 06-25-2014 12:41 PM

Re: Alarm sounds when cranking - Jeep turns off
Thanks for the reply. Awesome site.

EVIC? Sorry, I'm dont have any mechanical experience. Just learning as I go and when an issue arises, I start reading online.

The remote will unlock all doors except the driver's door.

Interesting that you should mention the pass. door. A few months ago I had to reconnect a wire in the boot of the passenger side door to correct an issue with interior lights staying, passenger door open message, battery drain.
I check boot wiring but didnt notice anything coming undone.

Side note... we have a very rainy few days and the issue happened the next day. Maybe moisture somewhere?

Once again, thanks for the guidance. It can be a overwhelming situation (trying to avoid a large repair bill).


jironman 06-25-2014 12:56 PM

Re: Alarm sounds when cranking - Jeep turns off
Sorry, I got it. Electronic Vehicle Info Center.

jironman 06-25-2014 01:01 PM

Re: Alarm sounds when cranking - Jeep turns off
I've also read a few posts about the anti theft system. ??? Thanks.

Frango100 06-25-2014 01:34 PM

Re: Alarm sounds when cranking - Jeep turns off
1 Attachment(s)
That the remote unlocks all doors except the drivers, is another pointer towards the PCI data bus. The drivers door unlocks via the drivers door module, which gets the signal via the PCI bus from the passenger door module. All other doors are hard wired to the passenger door module.
Rain can be the culprit. Do you have a multimeter, so that you can check the voltage between pin 2 from the diagnostic plug left under the steering wheel and a known good ground? If the voltage is 0 V, then i would start checking connector C200 up in the passenger footwell area against the bulkhead. It is known that water can enter this connector, making the pins green (corrosion) and causing a short in the PCI bus. I would get some dielectric grease and contact cleaner to make it all work again. In attached page you can see the location (more or less:rolleyes:) of connector C200.
Since the PCI bus wire also runs through both front door boots, it would be a second point to check (for broken wire)

jironman 06-25-2014 02:44 PM

Re: Alarm sounds when cranking - Jeep turns off
No, I don't have a multimeter. But I'll get one for sure. It appears to be an essential piece of equipment. Any recommendations? By a good ground, do you mean any metal surface in the area? I'm definitely going to check it out as suggested.

Side note: I keep reading about anti-theft or SKIM issues causing similiar symptoms. Do you think they could be related?

Sorry to ask so many questions. But from reading the site, you seem to know a ton about this this vehicle. Thanks again.

Frango100 06-25-2014 03:21 PM

Re: Alarm sounds when cranking - Jeep turns off
The skim also connects to the PCI bus, so when the PCI bus is dead, the PCM will not get the key ok message from the skim and the engine will run for 3 seconds and shut off. Same thing for the BCM ( body control module) which has the alarm function in it. No PCI bus means it will not receive the disarm message.
Since you don't have a multimeter, i would go directly to the C200 connector. Any simple multimeter for 15 bucks or so is a handy investment (especially when you own a jeep):D

jironman 06-25-2014 08:45 PM

Re: Alarm sounds when cranking - Jeep turns off
Hi again. Got a multimeter for $20 bucks. Not bad. Checked pin #2. Got a voltage of 4.9 to 5.7 (checked a few times). Any suggestions? Thanks for the help.

Frango100 06-25-2014 10:07 PM

Re: Alarm sounds when cranking - Jeep turns off
I still would check connector C200 first. Moisture or corrosion can cause a short between the bus connector pin and an other feeder pin running next to it. The bus voltage is at least too high, so now we have to find out why. If you will not find anything strange in connector C200, i would check both front door boots for broken wires. If this is also ok, then it will become a funny job, because then all components connected to the bus, must be disconnected one by one, until the bus voltage is back to 2.0-2.5 V.
On older WJs there was a disconnect plug under the steering column, where all components could be disconnected by just removing one shorting cap (except PCM and SKIM, they will always stay on the bus). Then one at a time the several components could be connected again, until the bus voltage went out of specs, and the fault was found. Unfortunately after 2003 they decided that this disconnect plug was not necessary anymore and removed it. Now you will have to go to each component and disconnect it one by one, until the bus voltage is back to 2.0-2.5 V. There are quite some components on the bus; PCM, TCM, BCM, SKIM, door modules, AC head unit, radio, ABS controller, airbag control module, instrument cluster, EVIC, radio amplifier, rain sensor, intrusion transceiver module, CD changer, adjustable pedals module and seat module:eek: (maybe i even forgot something). So 95 % of the jeeps control modules are connected to this bus, which makes trouble shooting an interresting thing:confused:

jironman 06-26-2014 08:14 AM

Re: Alarm sounds when cranking - Jeep turns off
Follow up:

I checked C200 as well as an identical box right above it(?). In removing the cover panel, I discovered that there was a bit of water under the floor mat!?! My wife later mentioned that during all the rain she was forced to drive through a couple deep puddles during the rainy days. It went unnoticed because of the plastic film under the mat. So I proceeded to remove the C200 and the other one. In doing so, there was a little bit of water at the bottom of each. However there was no corrosion. I didnt have any cleaner or dielectric grease. So I did my best to dry it out (towel & hair dryer). So I reconnected everything. I did hear a few clicking noises coming from under the hood? But it cranked and I let it run for 10 mins. The check engine light was on though. So I turned it off while I took care of a few things (I even used the remote to lock it out of habit and it worked, sound and function). I went back thinking I'd like to check the gauges & EVIC to see what was going on with them. It cranked fine however the EVIC isnt coming on and the dash guages arent working(they moved but then went to zero). On one attempt the clusters were lit up. ??? Unfortunately I had to get to work so my progress stalled. So I turned it off and then the remote once again wouldnt lock the driver door.

Maybe disconnect the battery?
Maybe start over and clean, dry, and apply the dielectric grease to be sure?
The check engine light confuses me.?
Hopefully nothing serious...
Any thoughts?

Once again thanks for your help. It is definitely appreciated.


Frango100 06-26-2014 10:05 AM

Re: Alarm sounds when cranking - Jeep turns off
PCI bus problems can be hard to solve. Did you check the bus voltage after cleaning the C200 connector? I would get some contact cleaner to spray the connector well, to remove any evidence of water. (both side, connector and receptacle). That it started normal now seems to point that you are on the right track.
You could check fault code set in the PCM doing the key dance, but only when the PCI bus works: ignition switch off/run three times and leave in run at the third time. Odometer will show DONE when all ok, or any fault code(s). I bet it has to do with loosing the PCI bus

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