I had to leave town and didn't get a chance to troubleshoot it yet, but I saw the voltage was right at 12 and not charging. It was probably running off just the battery. I restarted it later and the voltage was back to normal, then I restarted it again and it was back to 12. When I get home I'll have the alternator checked. I know the voltage regulation is controlled by the PCM but where's the regulator?
Voltage regulator??
Neil
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I had to leave town and didn't get a chance to troubleshoot it yet, but I saw the voltage was right at 12 and not charging. It was probably running off just the battery. I restarted it later and the voltage was back to normal, then I restarted it again and it was back to 12. When I get home I'll have the alternator checked. I know the voltage regulation is controlled by the PCM but where's the regulator?
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+1. Bad/Failing Alternator.
If it's an original, it's simply due.
IndyDurango
If it's an original, it's simply due.
IndyDurango
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+2 on the bad alternator
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Wasn't the alternator (I thought it was too.) I changed it last weekend and voltage on the dash was good all last weekend and then yesterday the wife tells me the Air Bag, Check Gauges and Check Engine lights came on. I checked and once again the voltage was low. Now what I didn't do last weekend was check the voltage at the battery before I changed the alternator because my Fluke meter was broken. Right now it's 14.3 volts at the battery with it running but the dash and scan gauge show the PCM is only seeing 11.4 volts. The CELs are 743, 7753 and 1765 which are tranny related for open/shorted 12V circuits controlled by the PCM. The dash lights could also be PCM voltage related. My neighbor is a mechanic and thinks it may be the PCM that's bad. A local junkyard has a 99 5.9 PCM for $100 but I couldn't get it today. Hopefully I can Monday and that's the problem. I'll have to figure out what to do if the stock PCM fixes it as my current one is a Mopar Performance PCM.
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Keep us posted. I'm running a Federal PCM right now as my Cali PCM needs to be fixed, it runs for a little bit and then shuts down for minutes or hours. I figured out how to get it running, but have a temp PCM in place until the Cali one is repaired.
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Here are some guys that repairs them for anywhere from $200-$300 depending how extensive the damage is.
http://ecmtogo.com/ECMTips2.htm
http://ecmtogo.com/ECMTips2.htm
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sounding more and more like the voltage regulator that's build into the PCM
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Fingers crossed. I got the JY PCM and the voltage came right up and the check engine light went off. Hopefully I got the GO part and I'll have to see about the GET UP part. It's noticeably down on power from the Mopar PCM. There was a Mopar PCM for sale on eBay a few weeks ago, maybe it didn't sell?? I'll look into SCT or see about repair of the Mopar PCM.
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I've repaired a few of them and some are repairable while some aren't. It just depends on how extensive the damage is and, yes, they're heavily siliconed to keep people out.
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I have a 4.7 PCM if anyone's interested.
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that's what makes this a great club! :clap: any idea on where I can find one for a 99 5.9 4x4 D, preferably a MPP PCM?
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