Trying to understand 5 speed PCM swap options - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > ZJ Grand Cherokee Forum > Trying to understand 5 speed PCM swap options

SPARTAN LOCKERS are on sale BIG TIME at ROCKRIDGE 4WD!ROCKRIDGE4WD Introduces a NEW Jeep Wrangler JK *led* tail ANOTHER Rockridge4wd Creation!! Spare Tire Carrier Delete

Reply
Unread 01-28-2014, 12:19 PM   #1
urbex
Registered User
1996 ZJ 
 
Join Date: Dec 2008
Location: Glendale, AZ
Posts: 21
Trying to understand 5 speed PCM swap options

It's been about a year since I put it together, and now I'm finally getting around to cleaning up the install, part of which is deciding what to do about the PCM.

I've read countless threads on here and other forums, and am still slightly unsure of what I need to get/do. I understand that I should be able to plug in a PCM from a similar year Ram or Dakota with the 318 and manual trans, but then I also see the scores of "for some unknown reason, Chrysler PCMs seem to go bad from just sitting on the shelf", which as an electronics tech makes absolutely no sense to me. Then I read that some PCMs are married to the SKIM module, which will cause a no start condition if swapped into another vehicle, which I suspect is the reason some of these PCMs seem to go bad.

But then it also appears that '97 is the year that these SKIM computers started appearing. I'm also making the assumption that same year PCMs should be able to communicate with my existing gauges OK. So if I get a '96 PCM to match my '96 Jeep, the SKIM and gauges shouldn't be a concern to me.

But that still leaves the issue of potential cruise control problems, and factory immobilizer/alarm problems. If I lose the factory immobolizer/alarm, that's really not an issue to me. I already have other passive and active kill switches in the Jeep, and since the factory keyfobs died a long time ago, it's really more of an annoyance now. Losing cruise would kind of suck though.

Is there a way to tell which PCM I would need based on part number? Or another way to tell?

There's also another kicker for me - I would need to get whatever I get flashed with my current VIN for emissions (yep, already called the emissions dept, was told a VIN mismatch would be an instant fail). Which makes me wonder if my better option would be to send my current PCM off to some place like B&G, though I don't need any of the performance tuning done.

urbex is offline   Reply With Quote
Unread 01-28-2014, 01:28 PM   #2
Oldfrog
Web Wheeler
1997 ZJ 
 
Join Date: Feb 2008
Location: Louisiana/Texas
Posts: 3,603
Dont know the entire answer, but as far as I know, the PCM doesnt need to be flashed. I've installed 4 in my 97 and never had to flash any of them. (a bad o2 sensor was taking them out, is my theory) The VIN isnt stored in the PCM on the 97 and I think 96-98 PCMs are all the same.
__________________
Cajun Recipes and Fishing tips

Words of wisdom, Posted by Zeejay:
"..it's not air, it is the opposite of air... suckage so to speak."

Stalling? Work through Zeejay's list
Oldfrog is offline   Reply With Quote
Unread 01-28-2014, 01:47 PM   #3
urbex
Registered User
1996 ZJ 
 
Join Date: Dec 2008
Location: Glendale, AZ
Posts: 21
Oooh...much helpful there! I was under the impression that ALL OBD-II computers had the VIN flashed in them, regardless of make/model, thus the concern for emissions testing time when they jack into the computer.

EDIT: Started a different tack in my Googling, and found a thread on another forum for Mass emissions testing that sounds similar to the way Arizona does it - they just jack into the diagnostics port, and run a code scan. If there are no active codes, you pass, and at least for their system, even if the VIN was flashed in the PCM they don't have a way to verify it. That doesn't come into play until 2000 when the CAN-BUS stuff started getting used. They also mentioned that although B&G can strip the auto trans programming, and change the VIN, they still consider it a custom tune with a $430 cost (I did call B&G earlier, had to leave a message for the tech...still waiting on a call back). Ouch.
urbex is offline   Reply With Quote
Unread 01-28-2014, 02:27 PM   #4
970001zj
Registered User
1997 ZJ 
 
Join Date: Feb 2012
Posts: 1,985
dakota or ram manual transmission ecu but someone will
__________________
http://www.jeepforum.com/forum/f22/its-jeep-grand-cherokee-you-1443132/#post14516738
970001zj is offline   Reply With Quote




Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.