Refer to "57.HVAC Control 7A.Troubleshooting(Auto A/C) diagnostic system check-auto A/C controls".
1) Turn OFF the ignition switch.
2) Connect the scan tool.
3) Turn ON the ignition switch.
4) Observe the ECM DTC information with a scan tool. Is a DTC set?
Yes
Go to the applicable DTC diagnosis.
No
1) Clear the DTC with a scan tool.
2) Turn OFF the ignition switch.
3) Start the engine.
4) Observe the DTC information with a scan tool.