GMC specific DTC OBD2 code: P1646 Driver 1 Line 6
GMC specific DTC OBD2 code: P1645 EVAP Solenoid Output Circuit
GMC specific DTC OBD2 code: P1644 TP Output Circuit
GMC specific DTC OBD2 code: P1643 Engine Speed Output Circuit
GMC specific DTC OBD2 code: P1642 FC Relay 2 And 3 Control Circuit
GMC specific DTC OBD2 code: P1641 FC Relay 1 Control Circuit
GMC specific DTC OBD2 code: P1640 Driver 1-Input High Voltage
GMC specific DTC OBD2 code: P1639 5 Volt Reference 2 Circuit
GMC specific DTC OBD2 code: P1638 Generator F-Terminal Circuit
GMC specific DTC OBD2 code: P1637 Generator L-Terminal Circuit