DTC U012087 Lost communication betwen the PCM and Alternator module.

2007 VOLVO XC90
125,000 MILES • 3.2L • 6 CYL • TURBO • AWD • AUTOMATIC
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FRANKYBALE
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Alternator light come on after a few minute the car running. I've installed two Alternator from the Dealer and checked the continuity wire which goes from Alternator to PCM.
Dec 10, 2014 at 8:33 PM
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STRAILER
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It sounds like it is the PCM that has gone bad but to be sure here is a guide and a alternator wiring diagram to help you do some testing.

https://www.2carpros.com/articles/how-to-check-wiring

If it checks out get a used PCM and swap it out which should fix it.

Please let us know what happens so it will help others.

Cheers, Ken

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Aug 23, 2017 at 9:07 PM