Diagnostic Aids

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The following conditions must be met in order for the ECM to turn on the compressor clutch:

Battery voltage is between 9-16 volts.
Engine coolant temperature (ECT) is less than 123°C (253°F).
Engine speed is less than 4760 RPM.
Engine speed is more than 600 RPM.
A/C high side pressure is between 2929-269 kPa (425-39 psi).
Throttle position is less than 100 percent.
Evaporator temperature is greater than 0°C (32°F).
ECM does not detect excessive torque load.
ECM does not detect insufficient idle quality.