A/C Compressor Clutch Relay Circuit
2007-2012 Nissan Altima 2.5L 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
Nissan 200SX
1995-1998 1.6L I4 GA16DE
Nissan 200SX SE-R
1995-1998 2.0L I4 SR20DE
Nissan 240SX
1995-1998 2.4L I4 KA24DE
Nissan 300ZX
1990-1996 3.0L V6 VG30DE
Nissan 300ZX Twin Turbo
1990-1996 3.0L Twin-Turbo V6 VG30DETT
Nissan 350Z
2003-2006 3.5L V6 VQ35DE
Nissan 350Z
2007-2009 3.5L V6 VQ35HR
Nissan 370Z
2009-2020 3.7L V6 VQ37VHR
Common Questions
What does code B0640 mean on a 2007-2012 Nissan Altima?
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 Nissan Altima?
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 2007-2012 Nissan Altima?
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.