B0621
Ambient Temperature Sensor Circuit - HVAC
2002-2005 Audi A4 3.0L V6 🇨🇦
Low SeverityBody
Description
Malfunction in the ambient (outside) temperature sensor used by the automatic climate control system.
Symptoms
- Incorrect outside temp display
- Auto climate control not adjusting for outside temp
- A/C compressor may not engage
- Defrost strategy incorrect
Common Causes
- Faulty ambient sensor
- Sensor mounted near heat source
- Wiring damage
- Sensor connector corroded
Diagnostic Steps
- Compare sensor reading to actual outside temperature
- Inspect sensor location for heat sources
- Test sensor resistance
- Check wiring
- Inspect connector
Repair Notes
Replace ambient temperature sensor. Ensure it is properly mounted away from heat sources.
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
B0621 on Other Vehicles
Common Questions
What does code B0621 mean on a 2002-2005 Audi A4?
B0621 stands for "Ambient Temperature Sensor Circuit - HVAC". Malfunction in the ambient (outside) temperature sensor used by the automatic climate control system.
What are the symptoms of B0621 on a Audi A4?
Common symptoms of B0621 include: Incorrect outside temp display, Auto climate control not adjusting for outside temp, A/C compressor may not engage, Defrost strategy incorrect.
What causes B0621 on a 2002-2005 Audi A4?
Common causes of B0621 include: Faulty ambient sensor, Sensor mounted near heat source, Wiring damage, Sensor connector corroded.