New PCM, now won't start. - 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 > New PCM, now won't start.

Rockridge 4WD IS Taking Zone Offroad Suspension Lift Kits Rough Country Jeep Suspension Deals at Rockridge 4WD!Looking to re-gear?! CRAZY DEALS ON YUKON GEARS right here

Reply
Unread 11-11-2013, 11:03 PM   #1
Nolvck
Registered User
1996 ZJ 
 
Join Date: Aug 2012
Location: Dallas, Texas
Posts: 18
New PCM, now won't start.

Hello again, thanks for looking. Hoping someone is able to help me diagnose my headache... I had a weird speed sensor issue and determined my PCM was trash. Ordered a new one (programmed to my vin) and got it in today. With more excitement than a toddler on Christmas, I ran to my garage and installed what I thought was going to fix my rig. She started up and ran great for about a minute then shut off. With fear in my eyes, I turned the key and tried to start her again... but no dice. Motor turns over and wants to start but falls short. I replaced battery and terminals a few days ago, and didn't even consider them to be a problem, until I tried starting her again and my check gauges light came on. My battery gauge sits at zero and my battery completely drained in a matter of minutes. Starting to think the alternator took a crap but not sure why it ran fine before with a **** PCM and bad battery and term. Fuses and everything tested fine.

So here's the quick play-by-play...
-NEW PCM
-started then died.
- cranks but won't start.
-check gauges light.
-battery gauge at 0
-new battery and terminals
-NO CEL

Nolvck is offline   Reply With Quote
Unread 11-11-2013, 11:42 PM   #2
JasonStebbins
Obv
 
JasonStebbins's Avatar
1997 ZJ 
 
Join Date: Jan 2009
Posts: 3,128
]How did you determine the PCM was bad in the first place? Have you had the charging system tested? Is the current PCM new/used/remanufactured? Where did you get it? The voltage regulator is part of the PCM on these models. Does your Jeep have a security system? If you got a PCM from a ZJ without one, it will shut down automatically from the fail safe.

Check the wiring for the oxygen sensors, if they are exposed and touching something it can fry the PCM.

Have you ruled out everything else such as the CPS and fuel pump?
__________________
Common ZJ problems and how to fix them by JasonStebbins
http://www.jeepforum.com/forum/f13/c...x-them-1432264

12 things to do when your ZJ stalls by ZeeJay1997
http://www.jeepforum.com/forum/f13/1...talls-1407423/
JasonStebbins is offline   Reply With Quote
Unread 11-12-2013, 01:57 AM   #3
Pugulis
Registered User
1996 ZJ 
 
Join Date: Aug 2010
Location: Long Island, New York
Posts: 991
Have you trie putting the old PCM back in? You could have easily gotten a defective PCM. Also, try disconnecting the map sensor and starting it.
__________________
[_][]☺[][][]☺[][_] 96' Grand Cherokee Laredo 265,000 miles and still going strong.
Pugulis is offline   Reply With Quote
Unread 11-12-2013, 02:51 AM   #4
Nolvck
Registered User
1996 ZJ 
 
Join Date: Aug 2012
Location: Dallas, Texas
Posts: 18
The old PCM had multiple solders busted. It was running rough and stalling pulled PCM and opened it up. Bought a refurb from "auto computers" online. My jeep does have a factory alarm that hasn't worked in over a year. I was thinking the CPS but was curious as to why this symptom would drain a new battery, made me think possible alt.
Nolvck is offline   Reply With Quote
Unread 11-12-2013, 08:36 AM   #5
Oldfrog
Web Wheeler
1997 ZJ 
 
Join Date: Feb 2008
Location: Louisiana/Texas
Posts: 2,936
Quote:
Originally Posted by Nolvck View Post
The old PCM had multiple solders busted. It was running rough and stalling pulled PCM and opened it up. Bought a refurb from "auto computers" online. My jeep does have a factory alarm that hasn't worked in over a year. I was thinking the CPS but was curious as to why this symptom would drain a new battery, made me think possible alt.

The bold text is your problem. Both of those outfits in Florida are....how shall I say it........crooks?
__________________
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."
Oldfrog is online now   Reply With Quote
Unread 11-12-2013, 12:38 PM   #6
JasonStebbins
Obv
 
JasonStebbins's Avatar
1997 ZJ 
 
Join Date: Jan 2009
Posts: 3,128
Quote:
Originally Posted by Oldfrog View Post
The bold text is your problem. Both of those outfits in Florida are....how shall I say it........crooks?
Yep. I've only read negative reviews about PCM's from Florida companies. You should repair your original PCM or else buy a Cardone brand. Here's a write up on how to do so.

http://www.jeepforum.com/forum/f13/9...tures-1303589/

The battery drain is probably from the faulty PCM. But I would get the charging system tested regardless.
__________________
Common ZJ problems and how to fix them by JasonStebbins
http://www.jeepforum.com/forum/f13/c...x-them-1432264

12 things to do when your ZJ stalls by ZeeJay1997
http://www.jeepforum.com/forum/f13/1...talls-1407423/
JasonStebbins 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.