Compressor Anti-Slugging Strategy (CASS)
WARNING: This page is about a different car, the 2008 Mercury Milan, 2008 Lincoln MKZ, and 2008 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
Liquid refrigerant may accumulate in the A/C compressor under certain conditions. To alleviate damage to the A/C compressor, the Compressor Anti-Slugging Strategy (CASS) is utilized.
CASS is initiated only under specific conditions:
- Ignition is OFF for more than 8 hours
- Ambient temperature is above -4°C (25°F)
- Battery voltage is above 8.5 volts during engine cranking
When these conditions are present, the PCM will activate the A/C control relay prior to cranking of the engine. The A/C control relay engages the A/C compressor for approximately 4-15 A/C compressor revolutions or a maximum of 2 seconds (depending upon vehicle application), allowing the liquid refrigerant to be pushed from the A/C compressor. CASS is initiated by the PCM regardless of the HVAC system settings.