Compressor Anti-Slugging Strategy

WARNING: This page is about a different car, the 2002 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.

Liquid refrigerant may accumulate in A/C compressor under certain conditions. To alleviate damage to A/C compressor, 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 25°F (-4°C).
Battery voltage is above 8.5 volts during engine cranking.

When these conditions are present, powertrain control module (PCM) will activate A/C control relay prior to cranking of engine. The A/C control relay engages A/C compressor for approximately 4-15 A/C compressor revolutions or a maximum of 2 seconds (depending upon vehicle application), allowing liquid refrigerant to be pushed from A/C compressor. CASS is initiated by PCM regardless of function selector switch position.