Bad ECM? alternator won't charge battery - Page 2 -
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post #16 of 19 Old 08-03-2013, 08:53 PM
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Doesn't the PCM regulate the alternator on our Jeeps? I don't think their are internal regulators on our alternators and if that is the case it is usually either the PCM, or more commonly a wire that is intermittently shorting. I would carefully check the wring very thoroughly. If that comes up short I think the dealer can test the PCM but I have no idea of the costs. If the wiring comes up good it is more than likely a PCM issue.

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post #17 of 19 Old 08-03-2013, 10:30 PM
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Originally Posted by Timmay82 View Post
Doesn't the PCM regulate the alternator on our Jeeps?
Yes it does...
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post #18 of 19 Old 07-12-2016, 08:48 PM
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I have a 2002 Liberty Renegade that has been displaying the battery light and I got a P0644 code. It turns out that the voltage regulator is INSIDE the bloody ECM! Flippin' GENIUS WORK Chrysler! How stupid can you get? Wait, you built this damned thing. That says enough.

Anyway, I found an easy solution. I just installed an EXTERNAL voltage regulator kit from Quick Start Alternators. ( It cost me $65.00 and is brilliantly easy to install. It includes absolutely everything needed and solved my problem. This is the way things were done before 1987 and they worked perfectly AND were easy to service. Now, it's all about driving you back to the dealer so that they can rape your wallet as much as possible! The Liberty proves that point very well!

So, if you want an EASY solution, use mine.

Good luck,

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post #19 of 19 Old 07-13-2016, 07:15 PM
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Do you own a TJ?...
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alternator , charging , ecm , pcm , voltage regulator

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