B0621low severityBody
Ambient Temperature Sensor Circuit - HVAC
on 1996 Toyota 4Runner 3.0L V6 · 4WD
What this code means
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.
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