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2021 TOYOTA 4RUNNER

4.0L V64WDAUTOMATICgas
1 active safety recall on this vehicle — view recalls
Repairs0Labor520Torque3907Fluid9DTC940Battery1Maintenance0Recalls1
B0621low severityBody

Ambient Temperature Sensor Circuit - HVAC

on 2021 Toyota 4Runner 4.0L 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

  1. Compare sensor reading to actual outside temperature
  2. Inspect sensor location for heat sources
  3. Test sensor resistance
  4. Check wiring
  5. Inspect connector

Repair notes

Replace ambient temperature sensor. Ensure it is properly mounted away from heat sources.

Other Body codes on this vehicle

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