Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2012 GMC Yukon XL, 2012 GMC Yukon, 2012 Chevrolet Tahoe, 2012 Chevrolet Suburban, and 2012 Chevrolet Avalanche. 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:
- Engine speed is greater than 600 RPM
- Engine speed is less than 4, 60 RPM
- A/C high side pressure is between 2957-151 kPa (22-429 psi)
- Throttle position is less than 100 percent
- Evaporator temperature is greater than 2°C (34°F)
- ECM does not detect excessive torque load
- ECM does not detect insufficient idle quality