Powertrain Control Module (PCM)

Based on signals from various sensors, PCM controls A/C compressor clutch operation through A/C compressor relay. To enable A/C compressor relay, PCM will provide a ground path. PCM will enable A/C compressor clutch operation whenever the engine is running and there is a request for A/C operation. PCM will disable A/C compressor clutch operation:

• During wide open throttle (greater than 90 percent).
• When high-side pressure is greater than a specified value. See A/C PRESSURE SENSOR .
• When ignition voltage is less than 10.5 volts.
• When engine speed is greater than 4500 RPM for 5 seconds or 5400 RPM.
• When engine coolant temperature is greater than 257°F (125°C).
• When intake air temperature is less than 41°F (5°C).