PCM/Voltage Regulator Help - Jeep Wrangler Forum

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Old 10-10-2013, 06:26 PM   #1
Join Date: Oct 2013
Location: Golden, Co
Posts: 2
Angry PCM/Voltage Regulator Help

I have a 98 TJ with the 4.0.
Been having issues with the charging system, voltage suddenly drops to zero, and check gauges light comes on, in addition to sporadic starting. Got battery and alternator tested, battery was bad (replaced it), alternator was good but voltage regulator was bad.
After doing some research, saw that voltage regulator is built into PCM (Dumb plan Chrysler).

Has anyone been able to successfully repair their PCM, and what steps did you take?
I am a college student and the cost of repairing it myself seems a lot more appealing, but what are some good sources for remanufactured PCMs?
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Old 10-11-2013, 12:00 AM   #2
RUBI 4 MY MRS's Avatar
Join Date: Feb 2011
Location: California/Nevada
Posts: 1,998
Haven’t seen but 1 person verify that this is a good solution but certainly cheaper than replacing the PCM.

External Regulator

I have read a lot of bad reports on reman PCMs so you may want to check this out. Help others with this problem by posting results if you use it.

External Regulator Conversion Kit for Jeep.

External Voltage Regulator Kit for Chrysler Dodge Jeep Vehicle Alternator ECU Bypass


'05 Rubi TJ Unlimited
'93 Toyota 4Runner
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Old 10-13-2013, 10:43 AM   #3
Join Date: Sep 2012
Location: Gaffney
Posts: 31
not sure if you fixed it yet..I had the exact same problem with my 97 tj and i had the alt tested at three seperate placed and it tested good so i replaced the pcm, the battery to no avail. I got exhausted and finally put it in the shop and it was a short in the alternator. new alt qnd it fixed the prob.
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Old 10-13-2013, 05:21 PM   #4
Join Date: Oct 2013
Location: Golden, Co
Posts: 2
Thanks for the input guys, I got the PCM apart, but visually saw nothing wrong, and didn't want to mess with resoldering the whole circuit board. The circuit board isn't potted like a lot of people have said.

I was able to find a PCM from a different year TJ. Does anyone know if a PCM from a different year will work if flashed?
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