GMC specific DTC OBD2 code: P1790 Transmission Control Module Checksum
GMC specific DTC OBD2 code: P1671 Driver 4 Line 1
GMC specific DTC OBD2 code: P1690 ECM Loop Overrun
GMC specific DTC OBD2 code: P1791 Transmission Control Module Loop
GMC specific DTC OBD2 code: P1672 Low Engine Oil Level Lamp Control Circuit
GMC specific DTC OBD2 code: P1691 Coolant Gage Circuit Low Voltage
GMC specific DTC OBD2 code: P1792 Transmission Control Module Reprogrammable Memory
GMC specific DTC OBD2 code: P1603 Loss Of SDM Serial Data
GMC specific DTC OBD2 code: P1621 PCM Memory Performance
GMC specific DTC OBD2 code: P1637 Generator L-Terminal Circuit