A/C Compressor Clutch Relay Circuit
1995-2005 Pontiac Sunfire 2.2L I4
Description
Malfunction in the A/C compressor clutch relay circuit. The relay controls engagement of the A/C compressor.
Symptoms
- A/C not blowing cold air
- Compressor clutch not engaging
- A/C works intermittently
- Relay clicking
Common Causes
- Faulty A/C clutch relay
- Relay control circuit issue
- Low refrigerant triggering cutoff
- BCM or PCM relay driver failure
- Corroded relay socket
Diagnostic Steps
- Check A/C clutch relay
- Test relay with jumper wire
- Check refrigerant pressure
- Test relay control signal from PCM/BCM
- Inspect relay socket for corrosion
Repair Notes
Replace A/C clutch relay. If relay keeps failing, check compressor clutch current draw.
Related Codes
Other Body Codes
- B0001Driver Frontal Stage 1 Deployment Control
- B0002Driver Frontal Stage 2 Deployment Control
- B0003Passenger Frontal Stage 1 Deployment Control
- B0004Passenger Frontal Stage 2 Deployment Control
- B0005Driver Knee Airbag Deployment Circuit
- B0006Passenger Knee Airbag Deployment Circuit
- B0007Rear Left Side Airbag Deployment Circuit
- B0008Rear Right Side Airbag Deployment Circuit
- B0010Driver Side Airbag Deployment
- B0011Driver Side Airbag Deployment Circuit Open
B0640 on Other Vehicles
Pontiac Aztek
2001-2005 3.4L V6
Pontiac Bonneville
1990-1999 3.8L V6
Pontiac Bonneville
2000-2005 3.8L V6
Pontiac Bonneville GXP
2000-2005 4.6L V8
Pontiac Bonneville GXP
2000-2005 4.6L V8 Northstar
Pontiac Bonneville SSEi
1992-1999 3.8L Supercharged V6
Pontiac Bonneville SSEi
1992-1999 3.8L V6 Supercharged
Pontiac Firebird
1993-1997 3.4L V6
Common Questions
What does code B0640 mean on a 1995-2005 Pontiac Sunfire?
B0640 stands for "A/C Compressor Clutch Relay Circuit". Malfunction in the A/C compressor clutch relay circuit. The relay controls engagement of the A/C compressor.
What are the symptoms of B0640 on a Pontiac Sunfire?
Common symptoms of B0640 include: A/C not blowing cold air, Compressor clutch not engaging, A/C works intermittently, Relay clicking.
What causes B0640 on a 1995-2005 Pontiac Sunfire?
Common causes of B0640 include: Faulty A/C clutch relay, Relay control circuit issue, Low refrigerant triggering cutoff, BCM or PCM relay driver failure, Corroded relay socket.