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P1605 Diagnostic Trouble Code Discussion for November 2007

Diagnostic Communication Line Malfunction


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Trouble Ticket Help Requests for DTC P1605
Help Request Posted
1999 Cadillac DeVille 4.6L No Start, MIL Lamp on, VIN: 1G6KD54Y1X
P1605: Loss Of HVAC Serial Data. Vehicle won't start unless headlight switch is on. No dash activity unless headlight switch is on. Alarm sounds when anything is done... open door, turn ign, start eng. Trans is not shifting, 2nd gear only (no 12v). All fuses are good and have 12v. Relays chec...
November 12, 2007
1999 Cadillac DeVille 4.6L No Start, MIL Lamp on, VIN: 1G6KD54Y1X
P1605: Loss Of HVAC Serial Data. Vehicle won't start unless headlight switch is on. No dash activity unless headlight switch is on. Alarm sounds when anything is done... open door, turn ign, start eng. Trans is not shifting, 2nd gear only (no 12v). All fuses are good and have 12v. Relays chec...
November 12, 2007