For 1990-2009 cars

This master DTC list includes all applicable DTCs in alphanumeric order with descriptors.

The GM LAN modules on this vehicle also support DTC Symptom information.

DTC | DTC Descriptor | Module That Sets the DTC | Diagnostic Procedure
--- | --- | --- | ---
1 | In-Car Air Temperature Sensor Error | HVAC | DTC 1
2 | Ambient Air Temperature Sensor Error | HVAC | DTC 2
3 | Coolant Temperature Sensor Error | HVAC | DTC 3
4 | Air Mix Door Error | HVAC | DTC 4
5 | Sun Sensor Error | HVAC | DTC 5
6 | Power Transistor Error | HVAC | DTC 6
7 | Max-Hi Relay Error | HVAC | DTC 7