Go Back   Jeep Garage - Jeep Forum > Jeep Platform Discussion > Grand Cherokee - WJ > Troubleshooting/Problems

Join Jeep Garage Today
Reply
 
Thread Tools Display Modes
 
  #13  
Old 07-17-2012, 02:48 PM
Member
 
Join Date: Jun 2012
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 859
Father Tiresias is on a distinguished road
Re: Immobiliser Problem?

Well, the rain here in the UK stopped long enough for me to have another look at this problem tonight. On went a fully charged battery and again it just cranked without starting. However, I did notice that regardless as to whether the alarm is set or not the VTSS indicator on the top of the dash board is permanently on. I'm 100% positive that before this problem started the indicator was only on when the alarm system was set. The alarm seems to operate as it should, indicators flash and doors lock when it is set. Indicators flash, doors unlock and courtesy lights turn on when it is unset. If I sit in the car with the alarm set and move around the alarm goes off. This leads me to think that the alarm functions are working but the immobilizer is not and the car is stuck with the immobilizer active.

I'm assuming that if the immobilizer is active the PCM is shut down which, if it is the centre of the can bus communications, would explain why I cannot get a code reader to connect to it. Is there any way to remove or bypass the immobilizer system? Is the immobilizer a seperate module somewhere or is it part of the BCM?

Do these suffer from the same problem as the P38 Range Rover whereby the key can get out of sync with the immobilizer preventing it from shutting off? Can it be re-synced?

I'm really keen to get this back on the road as my Mercedes insurance is due at the end of the month and I'd rather insure the Jeep instead!!
__________________

__________________
Reply With Quote
  #14  
Old 07-18-2012, 09:46 PM
Frango100's Avatar
Premium Member

My Jeep: 2004 4.7L WJ
 
Join Date: Dec 2009
Location: Brazil
Posts: 4,801
Thanks: 9
Thanked 75 Times in 70 Posts
Rep Power: 525732
Frango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond repute
Re: Immobiliser Problem?

Eventhough the immobiliser system can prevent the engine from starting, if a wrong key is used for example, it shouldnt do anything with the PCI data bus (the WJs use the single wire PCI data bus and not the double wire can bus). So it doesnt shutdown the PCM, the PCM is just missing an input from the SKIM and in this way will prevent the engine from starting.
Attached a similar problem, where all gauges stopped working, but the jeep was still running; PCI Bus Issue
Sofar other more or less similar problems where solved with a new or rebuild PCM.
The SKIS immobilizer system consists of the SKIM (sentry key immobilizer module), which has an antenna which uses HF signals to detect a valid key, and the PCM.
__________________

__________________
Frank

JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
Monroe Reflex shocks / Pirelli Scorpion ATR 245/65/17 - Transgo reprogramming shiftkit.

VW Beetle 2.0 TSI 2013
My new toy
Reply With Quote
  #15  
Old 07-20-2012, 05:27 PM
Member
 
Join Date: Jun 2012
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 859
Father Tiresias is on a distinguished road
Re: Immobiliser Problem?

Thank you for that link, very interesting reading. Unfortunately the cost of a replacement PCM in the UK will be more than the vehicle is worth so unless I can find someone to rebuild the existing PCM its going to be scrap yard time for the car.

I'll scope the PCI bus over the next few days but it looks highly likely that the PCM is going to be the problem.
__________________
Reply With Quote
  #16  
Old 07-20-2012, 10:06 PM
Frango100's Avatar
Premium Member

My Jeep: 2004 4.7L WJ
 
Join Date: Dec 2009
Location: Brazil
Posts: 4,801
Thanks: 9
Thanked 75 Times in 70 Posts
Rep Power: 525732
Frango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond repute
Re: Immobiliser Problem?

No junkyard jeeps overthere where you can use the PCM from? Look for the P/N on the PCM and search on the internet for same.
I know that several companies in the states repair PCMs, but probably the shipping will be a problem. No friends or family who are traveling to the USA this vacation and could bring back a PCM?
Eventhough the PCM is lickely the culprit, it is still possible that an other component connected to the PCI data bus is bringing it down. Would be a bad experience to say the least, to repair or replace the PCM and then discover that some other component is the problem.
__________________
Frank

JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
Monroe Reflex shocks / Pirelli Scorpion ATR 245/65/17 - Transgo reprogramming shiftkit.

VW Beetle 2.0 TSI 2013
My new toy
Reply With Quote
  #17  
Old 07-23-2012, 03:34 PM
Member
 
Join Date: Jun 2012
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 859
Father Tiresias is on a distinguished road
Re: Immobiliser Problem?

I had a couple of hours to spare this evening so had another look at this and found the following:

Scoping the data lead on the OBD connector shows a pulse of 7.5V so it looks like the ECU is alive.

Next, unplugging the cam sensor and what I think is the crank sensor connector and measuring for the reference voltage, I have just under 5V on both connectors. However, plugging the crank sensor back in causes the cam sensor voltage to fall to 0V. If I plug the cam sensor in with the crank sensor disconnected the voltage stays present. So it looks like the crank sensor has failed.

Just to confirm, is the following the connector for the crank sensor?



I'm still a bit confused by this though. With both sensors disconnected the instruments still do not work and the cooling fan is still on constantly. I would have thought that with nothing dragging the voltage down these should both function properly? The VTSS light is also still on permanently.

Looks like I need to replace the crank sensor anyway. There appear to be loads of different possibilities. Can anyone tell me the correct part number for one for a 1999 4.0 petrol?
__________________
Reply With Quote
  #18  
Old 07-23-2012, 09:14 PM
Frango100's Avatar
Premium Member

My Jeep: 2004 4.7L WJ
 
Join Date: Dec 2009
Location: Brazil
Posts: 4,801
Thanks: 9
Thanked 75 Times in 70 Posts
Rep Power: 525732
Frango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond repute
Re: Immobiliser Problem?

The 7.5 V from the PCI bus and the 5 V for the sensors are different voltage signals. However there seems to be something wrong with the crank sensor if you loose the 5 V reference after connecting the crank sensor.
Attached another writing about PCI data bus diagnoses.
Im not familiar with the 4.0, so cant tell you if the connector is from the crank sensor, sorry.
Attached Files
File Type: pdf view.pdf (2.55 MB, 2 views)
__________________
Frank

JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
Monroe Reflex shocks / Pirelli Scorpion ATR 245/65/17 - Transgo reprogramming shiftkit.

VW Beetle 2.0 TSI 2013
My new toy
Reply With Quote
  #19  
Old 08-09-2012, 12:30 PM
Member
 
Join Date: Jun 2012
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 859
Father Tiresias is on a distinguished road
Re: Immobiliser Problem?

I finally managed to get the crank sensor out - damn ally corrosion on the bellhousing had stuck it fast, not good when its just about impossible to get to at the best of times!! There are no Jeep dealers anywhere near me so I'm going to order a new one on line. There appear to be about six different part numbers for these though. Does anyone know the correct part number for mine, 1999 WJ 4.0 litre.
__________________
Reply With Quote
  #20  
Old 09-08-2012, 12:39 PM
Member
 
Join Date: Jun 2012
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 859
Father Tiresias is on a distinguished road
Re: Immobiliser Problem?

Well, it wasn't the crank sensor as a new one made no difference. Looks like the ECU is fried. Probably going to scrap the car as I cannot justify spending more money on it.
__________________
Reply With Quote
  #21  
Old 09-16-2012, 06:06 AM
Member
 
Join Date: Jun 2012
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 859
Father Tiresias is on a distinguished road
Re: Immobiliser Problem?

Well, I've managed to locate a PCM, Skim module, BCM, keys and fobs from a 2001 model for a reasonable price (220). Just waiting for them to be delivered. Fingers crossed that it solves the problem!!
__________________
Reply With Quote
  #22  
Old 09-16-2012, 09:50 AM
Frango100's Avatar
Premium Member

My Jeep: 2004 4.7L WJ
 
Join Date: Dec 2009
Location: Brazil
Posts: 4,801
Thanks: 9
Thanked 75 Times in 70 Posts
Rep Power: 525732
Frango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond repute
Re: Immobiliser Problem?

Good to hear you are not going to scrap the jeep, that would have been a pitty. Success with the parts swap.
__________________
Frank

JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
Monroe Reflex shocks / Pirelli Scorpion ATR 245/65/17 - Transgo reprogramming shiftkit.

VW Beetle 2.0 TSI 2013
My new toy
Reply With Quote
  #23  
Old 09-22-2012, 12:06 PM
Member
 
Join Date: Jun 2012
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 859
Father Tiresias is on a distinguished road
Re: Immobiliser Problem?

I had a couple of hours to spare this afternoon so I thought I'd take another look at this. I changed the PCM, BCM + internal fuse box and the Skim module for items taken from a running vehicle. And..... it still has exactly the same problem.

So I'm thinking along the lines of an outstation fault. Possibly the front doors, instrument cluster or overhead console? Do any/all of these communicate via the coms bus? What would happen if I disconnect any/all of these? Would the engine normally still start?

The other possibility is a wiring loom fault. I'm thinking along the lines of the loom that runs around the rear of the engine.

Loosing patience now - the thought of scrapping it is ever more attractive.
__________________
Reply With Quote
  #24  
Old 09-24-2012, 02:35 PM
Frango100's Avatar
Premium Member

My Jeep: 2004 4.7L WJ
 
Join Date: Dec 2009
Location: Brazil
Posts: 4,801
Thanks: 9
Thanked 75 Times in 70 Posts
Rep Power: 525732
Frango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond repute
Re: Immobiliser Problem?

Yes, instrument cluster, EVIC, driver door and passenger door module, TCM, BCM, SKIM and anti lock brake module are all connected to the same PCI data bus. (and even more modules)
I think that most of the modules could be disconnected without problems to start the engine, the SKIM for sure not and the BCM im not sure.
I was reading about PCI bus problems and that the voltage normally is around 0-2V. Higher voltage could indicate a problem in one of the connected modules.
There seems to be a central connection point somewhere under the steering column where each module connects to and where each can be disconnected.
I would also check very well the cable looms under the hood for any chaving or heat damage to the insulation.
__________________

__________________
Frank

JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
Monroe Reflex shocks / Pirelli Scorpion ATR 245/65/17 - Transgo reprogramming shiftkit.

VW Beetle 2.0 TSI 2013
My new toy
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
first problem outback Trouble Shooting/Problems/Service 2 02-24-2012 05:44 AM
another problem please help tyler05wk Troubleshooting/Problems 0 01-09-2012 01:18 AM
What is the problem??? smack82 Troubleshooting/Problems Discussion 6 05-03-2011 04:07 PM
Might have a problem here scrivenerc Engine Performance/Intake/Exhaust 19 02-19-2011 06:49 PM
has anyone else had this problem? 99limited Audio, Video, Navigation & Electronic Modifications 14 04-01-2010 05:17 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 03:29 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community