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Ian Mills
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Ian Mills Enthusiast

Ian Mills

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So I'm trying to chase down some sort of electrical issue that results in lost communication and low voltage codes intermittently. I had previously suspected a bad ground or failing module but today I was driving, CEL came on, and I noticed that my voltmeter was hanging out at <12. 

I pulled over (the gauge came up a bit right when I came to a stop) and read the voltage at the battery and alternator with my multimeter. Both were reading between 12.9 and 13.2. That's not right... right?

The other questions is: is this another symptom or is this potentially what's causing all my communication codes (U1041, U1026, U0101, etc.) and low voltage codes (P0332, P0327, etc.)?

How low would the voltage need to dip momentarily for the computers to start throwing codes like that?

Ian Mills Enthusiast

Ian Mills

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I had the same issue this morning with the voltmeter showing significantly below 14. I read the voltage and it was 12.8. 

However, I turned the truck off and back on and the voltage was 14.7.

Would this be fixed with a new alternator?

The current alternator is only about 6 months old (Ultima R110073A)

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