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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
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