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P1638 Diagnostic Trouble Code Discussion for April 2009

TCM Internal - CAN 1 RAM Performance

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Trouble Ticket Help Requests for DTC P1638
Help Request Posted
2001 GMC Jimmy SLE 4.3L No Start VIN: 1GKDT13W81
P1638: Generator 'F' Terminal Circuit Malfunction. I am a Chrysler, Dodge, Jeep tech, not at all familiar with GMs. When cranking the engine in an attempt to start it, it sounds like it is too far advanced or firing order is off. We have removed #1 spark plug & brought the engine to TDC on #1 cylinder. Rei...
April 02, 2009