Possible causes

– Faulty Air Conditioning Clutch Relay
– Air Conditioning Clutch Relay harness is open or shorted
– Air Conditioning Clutch Relay circuit poor electrical connection

When is the code detected?

Code P0646 may be stored if the commanded signal from the AC Clutch circuit does not match the feedback signal.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P0646 DODGE Description

A/C clutch relay may also be referred to as A/C compressor clutch relay. A/C clutch relay circuit is monitored when ignition is on and battery voltage is greater than 10.4 volts.