1997 PCM after install issue

rick465

New member
The PCM on my '97 Grand Cherokee Laredo 6cyl died, so I replaced it. Now it will turn over but will not start. There is no key with a slash symbol, the key has no transmitter on it, I have locked and unlocked all the doors and tailgate many times with the key and the electric switch on the inside and I, long ago, lost the fob.

Please tell me there is something I can do other than having it towed to the dealer for a reprogramming for a tow charge and $150.00 from the dealer...

Looking for some help while I still have hair left!

THANKS GUYS!!
 

your PCM must be programmed to your vin to function properly. they are not simple buy at a bone yard and install. this is why the pcms are so expensive.
 
Right but is there a way to do that without towing the truck to the dealer to program it. They told me it has to be in the vehicle to be programmed, which makes sense, but surely there is an alternative...
 
on a 97? you don't have to program it. we bought one on ebay and plugged it into our 98 and it ran great. ours was a 98 limited with 4.0

did you buy that one brand new?
 

BASICS
History May help - WHY was PCM replaced - where dd you get replacement PCM?

Codes - what are the codes now?
KOEO -
12v at injectors - yes no
at coil - yes no
fuel pressure PSI?

Spark at plugs?
 
The PCM was replaced due to the stalling issue ect that goes with its failure. All codes pointed to PCM not CPS, fuel or something else. I could get it going by wiggling the cables or pressing on the PCM.
I got the first replacement PCM from EBay...it didnt work. The second I pulled from a rear-end wreck. After the first would not turn anything on. Now it turns on and turns over but will not start which appears to be a programming issue with the PCM, as best as my research and my 'non-dealer' mechanic can tell.
I would say there is spark at the plugs, I have no idea about the 12v at the injectors or the coil, do not know the PSI for the fuel and don't know what a KOEO is.
Everything worked perfectly before the PCM stalling issue. There were no codes, no fuel issues and no spark issues.
 
if you push on this one while someone turns the key does it start and run fine? maybe another bad one
 

I will gladly help BUT you will need to do some diagnostics.

How do you know there are no codes - I am hoping you have a scanner with live data.

BASICS
spark ?
12v at inj and coils ? Use a test light or Meter
KOEO = Key On Engine Off
PSI is fuel pressure a important test on fuel injected engines.
 
There is a place that deals in used PCMs. I'll post up if I find the name and link.

Is it possible either you or the doner vehicle have a SKIM and alarm system on the vehicle?


JPNinPA
Using Jeepz.com app
 
I have no tool to give live data. I can not get it to go, pushing on the PCM or any other wiggling wires or the like. No idea about the donor car but it was supposed to be a 97, Grand Cherokee Laredo, 2wd with a 6 cyl. I am only assuming mine has an alarm because I have been told that all 97 and after do. It has never gone off, there is no alarm or security light, there was a 'panic' button on the fob (when I had one) and the lights do not flash now and the horn does not sound.
No idea how to check the PSI on the fuel, my guess is I need a tool I don't have. I do have a multimeter...Can that be used to test the voltage at he inj and coil? I'll hunt up some vids on that.
But all that not withstanding...is there no way to reprogram the PCM (if it needs it) other that towing the truck to the dealer or someone with a proper computer and jeep codes?
 
Kinda what I figured... Thanks for the help!! You guys were about the only ones who were helpful!!! Great job!
 
Towed the thing to the dealer today. They called this afternoon and said it is the wrong PCM because this PCM has security on it and there is no alarm on my Jeep.
Another PCM is all I can figure to do. The correct one would not need reprogramming, just plug and play. Which I thought would be the case from the beginning.
I have read the thread on another board "Resetting the PCM Adaptive Memory" Resetting the PCM Adaptive Memory - JeepForum.com I am not sure if resetting the adaptive memory is what this needs or not. If the rain lets me I'll try it before work in the morning. All the PCM's I have so far have been junk yard and EBay buys, not remanufactured.
If that does not work I have 2 questions. Is there a way to use this "wrong" PCM? Can it be reset back to factory? and If not, how do I know if the next PCM I might get had security on it unless I or whoever I get it from knows? Or is a reman my only option?
THANKS!!!!!!!!!!
 

dang, that security system gets a lot of people. I don't know if you can get it to run since your jeep doesn;t have it, though. I know a lot of the 94, 95, 96 models didn;t have security on them
 
Any chance you have original PCM ?

Plan B order a remanufactured PCM- they only need mileage and vin, should be plug in then only @200$.

I have a concern with WHY original failed - do not want to replace if conditions not corrected.
 

There is a place that deals in used PCMs. I'll post up if I find the name and link.

Is it possible either you or the doner vehicle have a SKIM and alarm system on the vehicle?


JPNinPA
Using Jeepz.com app

Oh so it is a is SKIM issue.

I'll look again later for the place that deals in used PCMs and post up
http://allcomputerresources.com

JPNinPA
Using Jeepz.com app
 
Last edited:
Call another dealer or two before you pay for another PCM. From my dealings with pcm remanufacturers , there is only one per generation and every feature is just a matter of programming the unit. this includes things like auto door locks (locking doorss when the transmission is put in drive, head lights going on when wipers are turned on when the head lights aree set to auto, daytime runninglights enabling and disabling security and more so I dont see why they cant disable security on your PCM...
 

All my research tells me that once security is enabled that it can't be turned off and a Jeep with no security will never start with the PCM having security enabled. The PCM has to be totally reprogrammed, which a dealer can not do. I discussed this all with Kolak who seems to be pretty much THE expert on this and confirmed what I found. I sent the PCM to him and he is getting it taken care of for me. VERY helpful and a little (in some cases a lot) cheaper than anyone else. Right not I can highly recommend him. I am assuming this will work and will follow up when I find out. Probably next week. I reached him at kolak@aol.com.
Fingers crossed...
 
Back
Top