PCM Compressor Control Logic

The PCM will monetarily shut off the compressor under the following conditions.

Engine Temperature

A/C off at 118°C (244°F)
A/C on at 113°C (234°F)

Wide Open Throttle (WOT)

A/C off for 15 seconds if TP sensor is greater than 95% automatic transaxle, 90 percent manual transaxle. Back on with TP sensor less than 95 percent after two seconds.

Compressor Overspeed Protection (COSP)

A/C Off if engine rpm is greater than 6375 rpm. A/C on if engine rpm is less than 4500 rpm for two seconds.

Evaporator Low Ambient Protection (ELAP)

If ambient air temperature is between 5°- 16°C (40° - 60°F) and vehicle speed is greater than zero the compressor cycles once every 90 seconds depending on inlet air temperature temperature and vehicle speed. The maximum time the compressor is turned off in this temperature range is 15 seconds.

High/Low Pressure Cut-Out Switch

A/C off if discharge pressure is greater than 2758 kPa +7/- 138 kpa (400 psi + 1/-20 psi) and back on at 1724 kPa +7/-345 kPa (250 psi + 1/-50 psi). Cooling fan will run for 180 seconds after A/C is turned off. A/C Off if discharge pressure is less than 276 kpa (40 psi).

Cooling Fan Logic

Fan On with A/C switch On. Fan Off at speeds greater than 113 km/h (70mph) for 180 seconds. Fan runs for 180 seconds after A/C is turned Off.