P0647 A/C Clutch Relay Control Circuit High

Definition: The P0647 code indicates that the Powertrain Control Module (PCM) has detected a high voltage condition in the A/C clutch relay control circuit.

p0647 – A/C Clutch Relay Control Circuit High

Typical Severity: Moderate

Common Causes

P0647 – A/C Clutch Relay Control Circuit High

Common causes:

• Faulty A/C clutch relay
• Short circuit in the wiring of the A/C clutch relay control circuit
• High resistance in the A/C clutch relay control circuit
• Faulty PCM (Powertrain Control Module)

 

Common Misdiagnosis

OBD2 Code: P0647

Description: A/C Clutch Relay Control Circuit High

Common Misdiagnosis: Replacing the A/C compressor or clutch without checking the relay or wiring issues.

 

Common Diagnostic Steps

OBD2 Code: P0647

Description: A/C Clutch Relay Control Circuit High

• Check the A/C clutch relay for proper operation and replace if necessary.
• Inspect the wiring and connectors in the A/C clutch relay control circuit for damage or corrosion.
• Test the power supply to the A/C clutch relay to ensure it is receiving voltage.
• Verify that the ground connection for the A/C clutch relay is secure and free of corrosion.
• Use a multimeter to check for continuity in the circuit between the engine control module (ECM) and the A/C clutch relay.
• If all other components are functioning correctly, consider testing or replacing the ECM as a last resort.