Chevy/GMC Duramax 04.5-05 LLY Discussion of Chevy and GMC Trucks with LLY Duramax Turbo Diesel Engines

p0642

  #1  
Old 09-08-2010, 10:54 AM
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Default p0642

Code: P0642
Modules: ECM
Description: 5-Volt Reference 1 Circuit Low Voltage

This tells me it could be anything with a 5v reference. I changed the oil pressure sensor, pedal assembly, getting a fuel pressure sensor, and possibly a MAP sensor, and i cleaned the ecm, plus reflashed it.
Truck runs normal up to about 45-50, then craps out starts rattling, no smoke though, pedal goes dead then comes back, oil pressure gauge goes crazy, but logging with efi shows no change in oil pressure. Will come back around and be normal til you pick up speed again, then repeats.
I've asked on every other diesel forum i'm a member of, not many seen the problem.
 
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Old 06-05-2016, 05:15 PM
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Default Po642 code also co569 and vo140 codes

Help please don't know where to start
 
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Old 06-06-2016, 12:02 PM
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I had to have the accelerator pedal reflashed
 

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