Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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.
- When engine coolant temperature is greater than 257°F (125°C).
- When intake air temperature is less than 41°F (5°C).
- When power steering load is greater than normal.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.