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P1639 Diagnostic Trouble Code Discussion for January 2013

5-Volt Reference 'B' Circuit Malfunction


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Trouble Ticket Help Requests for DTC P1639
Help Request Posted
2002 GMC Sierra 2500 SL 6.0L Hesitation, Misfire, MIL Lamp on VIN: 1GTGK29U22
P1639: 5-Volt Reference 2 Circuit Low Input. when it acts up ,running rough ,misfiring, there is about 9 volts @ the 5volt reference wire from pcm to tps.Note (this is a throttle cable truck not fly by wire).When tps is disconnected it straigtens out and doesnt act up.I've traced the wire back to pcm,and...
January 18, 2013