Check Engine Light w/ VMSpec Codes

July 01, 2021, 12:40:13 pm

Getting a check engine light. VMSpec is showing the following codes.

ENG SPN 627 2 Injector Power Invalid Data
ENG SID 251 50 Power Supply Invalid Data

No effect on drivability as far as I can tell. The M11 just purrs right along. Any reason I shouldn't just continue on down the road? Thoughts on where to look for troubleshooting?

Thanks!

Re: Check Engine Light w/ VMSpec Codes

Reply #1 – July 18, 2021, 09:33:32 am

Just to close this out for future searches. My check-engine light was caused by failed chassis batteries. With new batteries in, the fault has cleared and not returned.

Re: Check Engine Light w/ VMSpec Codes

Reply #2 – July 18, 2021, 09:49:37 am

I missed this one. I started seeing "Low Potential" on injector 6. That went on for a while. I checked connections, had the alternator "tested", and checked the start batteries individually for capacity. The culprit was the alternator. It was putting out but the voltage was low. We never saw this when we departed because all batteries are connected to a smart charger when plugged in at home ... only after a stretch of driving. And at the time it was no causing a check engine light just logging them, dozens of the same thing.

I switched to a Delco Remy 40si series brushless alternator. I had already switched to a smart zero voltage drop isolator. I think the LN alternator was actually OK, more than likely a bad sense wire connection. I put on all new wiring anyway. And like the much more efficient Delco alternator.

These codes are not always very obvious. They are clues to help solve problems.

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