Compressor Anti-Slugging Strategy (CASS)
WARNING: This page is about a different car, the 2005 Mercury Sable and 2005 Ford Taurus. 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:
- the ignition is off for more than 8 hours
- the ambient temperature is above -4°C (25 °F)
- battery voltage is above 8.5 volts during engine cranking
When these conditions are present, the powertrain control module (PCM) will activate the A/C control relay prior to the engine cranking. The A/C control relay engages the A/C compressor for approximately 4-15 revolutions of the A/C compressor 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 function selector switch position.