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Discussion Starter · #1 ·
Dear all

How can I bypass the imobiliser my car came with?
It is the European version of the 1997 tj. I will attach a photo of the imobiliser. I am under the impression that it is not working and has blocked the 5v output of the PCM
 

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Trace the wires find out where it connects.

Is if it is simply cut and spliced into a wire then you can remove it and spice the wire back together
 

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Discussion Starter · #3 ·
Trace the wires find out where it connects.

Is if it is simply cut and spliced into a wire then you can remove it and spice the wire back together

The imobiliser has 5 pins.

1- CCD bus (+)
2-CCD bus (-)
3- 12v (-) and pcm ground pins A31 & A32
4- 12v (+) and as well I find a little resistance( 50 to 70ohms on pins in the pcm for each injector, power steering pressure switch sense, ASD, and stop lamp switch sense)
5- fuse 7 in the glove box which is for Back-up LP EBL, ABS- and this one fuse I don't understand what it is for besides the obvious ABS

Any advice on what to do next and what that LP EBL mean?
 

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I’m not sure how those are wired in but seriously doubt they can deactivate the 5v outputs. If the immobilizer was somehow designed to block the 5v outputs you would find that if you tried to start it with the immobilizer still set (on) besides not starting, none of the gauges would respond. Most systems either cut the power to the starter so turning the key to start gets nothing, only silence, or they cut power to the ignition & you get crank, no start. The later SKIM option would allow start for about 3 seconds then die. That would work for about 3 starts then just give you crank, no start. That is the 3 most common types. How did yours work? And what is happening now? Crank, no start?

The best indication you have no 5v output from the PCM is when you turn the key to on (not to start) & none of the gauges move. Especially noticeable would be no volt or fuel gauge movement (as noted above).

Have you actually checked the 2 5v outputs to verify whether you are getting 5v?

I see you have a 1997, 2.5L. For some unknown reason most of the failed 5v output PCMs have been in that year & engine. I have seen some others & some of those have been caused by shorted sensors or their wiring so that is always a possibility. Especially if there is some (but lower than 5) voltage showing when checked.

I did a quick search of that immobilizer but could not find much info as to how it functions so any info you have on that might be helpful too.
 

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If it ties into CCD bus it easily could turn off fuel and/or spark not unlike skim

The euro export mandated this system from factory and as euro export have different PCM who knows how the integrated the anti theft mandated by Europe and it would be typical for Chrysler to modify skim to use remote instead of a chipped key




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If you could pass emissions with a swapped pcm perhaps a 97 xj or TJ pcm from non export

I drove my 98 TJ 4.0 5 spd a few days with a 97 xj 4.0 auto pcm and ran fine but since xj was auto got a cel for no TCM on bus
Other than that just plug and play


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Discussion Starter · #9 ·
Looks like it may actually be a version of skim...
Contact a European jeep dealer...
According to what I was able to find it is integrated and not able to be bypassed... the module and remotes are discontinued but it looks like there is or at least was an updated module and remotes available for @ $350

https://www.justanswer.com/jeep/7une9-jeep-wrangler-tj-97-jeep-tj-titled-europe.html
If you could pass emissions with a swapped pcm perhaps a 97 xj or TJ pcm from non export

I drove my 98 TJ 4.0 5 spd a few days with a 97 xj 4.0 auto pcm and ran fine but since xj was auto got a cel for no TCM on bus
Other than that just plug and play


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Gentlemen, so what should i expect? If i buy a non export pcm, will just plug it in, or should i do something with the wires going into the imobiliser?
 

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Discussion Starter · #11 ·
I’m not sure how those are wired in but seriously doubt they can deactivate the 5v outputs. If the immobilizer was somehow designed to block the 5v outputs you would find that if you tried to start it with the immobilizer still set (on) besides not starting, none of the gauges would respond. Most systems either cut the power to the starter so turning the key to start gets nothing, only silence, or they cut power to the ignition & you get crank, no start. The later SKIM option would allow start for about 3 seconds then die. That would work for about 3 starts then just give you crank, no start. That is the 3 most common types. How did yours work? And what is happening now? Crank, no start?

The best indication you have no 5v output from the PCM is when you turn the key to on (not to start) & none of the gauges move. Especially noticeable would be no volt or fuel gauge movement (as noted above).

Have you actually checked the 2 5v outputs to verify whether you are getting 5v?

I see you have a 1997, 2.5L. For some unknown reason most of the failed 5v output PCMs have been in that year & engine. I have seen some others & some of those have been caused by shorted sensors or their wiring so that is always a possibility. Especially if there is some (but lower than 5) voltage showing when checked.

I did a quick search of that immobilizer but could not find much info as to how it functions so any info you have on that might be helpful too.
Dear RUBI 4 MY MRS,

First of all thank you for your input into the topic i have opened couple weeks back here https://www.wranglerforum.com/#/topics/2375463?page=3 i did lots of checkS using the multimeter into the PCM and on the wires as well. I have reached to the conclusion very easy, thanks to you, that i did not have 5v output whatsoever. I was actually having 0.8v and 0.6v on them if i recall properly, any way it was 0.x V .I believed it was the PCM faulty because of that burn i found inside of it when i opened it. I told you about that and also i have attached a photo of it in the above mentioned post. That burn as i was telling you earlier goes to pin A22 into the PCM black connnector and according to the service manual it is going to fuse B + and into circuits A3and A14 which i have followed all the way to the light switch and i couldn't find an answer why it burnt the PCM in the first place..it still is a mistery to me now.

My TJ, after i have repaired the board was cranking with no start. No gas wasgoing to the injectors.

With no 5v on theboard i have externally supplied 5v and fired the engine and then i instantly got gas at the injectors and the car was starting but could not idle. Was shutting down immediately. If i cranked with the foot all the way on gas it ran for 2 seconds then stopped.
I have then assumed that there was something wrong with the ASD relay. Although the relay itself was functioning i have thought that there was something wrong with its wiring, so i have bypassed it. I started the engine, it was not working while idling but at 3000rpm revs it was running great and did not shut down after 2 secs as it used to do, it ran for good 20 sec and then smoke came out of the PCM. A part of the board was fried and melted and i checked a bit and found out that it was in charge of controlling the ignition coil.

Now with no PCM available and one on the way, ordered from flagship one, who by the way they say that they are working diligently to program it for five days now, i have recaped all issues i had, and according to some of the posts you shared with me-thank you- and other ones i have read online and youtube videos watched i have reached these conclusions:
1- PCM part which is controlling the step by step engine inside the AIC is either deffective or the imobiliser is shutting down the engine( The wiring was good and the AIC motor is giving me 56ohms resistence on both circuits inside it and no short circuit inbetween); besides this, the imobiliser has two wires going to the CCD bus so it can as well tell the PCM what to do
2- the ignition coil might send high voltage back to the PCM causing it to fry
3- the imobiliser is defective because no matter what button i press on it the car reacts the same :gauges not working, engine cranking and not starting. Because i have managed to start the engine only by bypassing the asd relay i am under the impression that the imobiliser is the problem. The other issue is that i do not understand why the pcm was fried in the first place and the second time as well !
 

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Discussion Starter · #12 ·
If you could pass emissions with a swapped pcm perhaps a 97 xj or TJ pcm from non export

I drove my 98 TJ 4.0 5 spd a few days with a 97 xj 4.0 auto pcm and ran fine but since xj was auto got a cel for no TCM on bus
Other than that just plug and play


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Which is the best place to buy one from?
 

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When I posted here I did not realize (at that time) that you were the same one I replied to on your other thread. So some got repeated here.

There are several thing to consider so I will try to address each.

Concerning the possibility of an external short burning the PCM. You say your 5v outputs were low but not 0.0v. I have seen this low output maybe between 0.5 & maybe about 1.5v which resulted from a short in one of the sensors pulling the voltage low. However when they tried the USB charger for testing it also was pulled low which sent us looking for the excessive draw. If I recall, once the shorted sensor was replaced I think everything returned to normal & the engine started, no apparent harm done. So you should check each of the 3 wire, 5v sensors for any shorting to ground including the sensor ground if you have not already done so.

Did you verify the voltage when you powered up using the charger?

Knowing your PCM was shorted & damaged & you reporting low 5v output makes it difficult to address the IAC which requires PCM operation to function. That may well be a result of the damage already done.

The IAC uses 4 wires, 2 (+) & 2 (-) to step up or down as needed. If one side was bad & it stepped completely closed the failed to step up you could get the no idle condition you had.

The same applies to the ASD relay which needs a ground signal from the PCM to energize. Perhaps already damaged PCM.

On that note, are you sure you did not mean c-3? That is the ASD relay control circuit which might explain the ASD issue. I do not find anything at a-3 & nothing at 14 on any of the 3 PCM connectors. Maybe one of the IAC circuits??


The coil driver operates on the ground side of the coil by pulsing ground signals to fire the coil. I have never heard of a coil essentially shorting & back feeding 12v into the ground circuit. Possible, I suppose. And depending how you bypassed the ASD maybe something like that fried the rest of the PCM. When I bypass a relay I jump across the 30 to 87 terminals so I still have the relay’s fuse in the path to protect from possible unexpected shorts.

As for your immobilizer, I had no idea it was a required factory equipped module when I posted above. I have no idea how it functions. If it interrupts the CCD bus that complicates things. Beyond that I have nothing else to add on that.

When you get the replacement PCM I would not have the immobilizer connected in case it operates like the later SKIM which if you started a non SKIM activated PCM the SKIM module would signal & activate it & there was no going back. If yours is now defective & maybe even the cause of your present situation I would certainly try to “bypass” it now with the new PCM. You might also consider using a lower amperage fuse for the a-22 PCM feed (fuse 6) when you install the new PCM in case there is a still undetected system short. Blowing the fuse rather than the PCM, you know…
 

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