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Home >> Toyota >> 2020 >> RAV4 XLE, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 62 (Heating / Air Conditioning System (HV) - Diagnostic Codes (1 Of 3)) >> AIR CONDITIONING SYSTEM (for HV Model) >> DTC B1412: Ambient Temperature Sensor Circuit [11/2018 - 02/2019] >> Description

DTC B1412: Ambient Temperature Sensor Circuit [11/2018 - 02/2019]: Description

WARNING: This page is about a different variant/trim than selected.

The thermistor assembly is installed in front of the cooler condenser assembly to detect the ambient temperature, which is used to control the air conditioning system AUTO mode. This sensor is connected to the air conditioning amplifier assembly and detects fluctuations in the ambient temperature. This data is used for controlling the cabin temperature. The sensor sends a signal to the air conditioning amplifier assembly. The resistance of the thermistor assembly changes in accordance with the ambient temperature. As the temperature decreases, the resistance increases. Conversely, as the temperature increases, the resistance decreases.

The air conditioning amplifier assembly applies a voltage (3.3 V) to the thermistor assembly and reads voltage changes due to changes in the resistance of the thermistor assembly (ambient temperature sensor).

DTC No. Detection Item DTC Detection Condition Trouble Area Memory
B1412 Ambient Temperature Sensor Circuit
  • Diagnosis condition: None
  • Malfunction status: Open or short in ambient temperature sensor circuit
  • Detection time: None (Present malfunction), continuously for 4 seconds or more (Past malfunction)
  • Thermistor assembly
  • Harness or connector
  • Air conditioning amplifier assembly
Memorized

HINT: 

If the ambient temperature is approximately -52.9°C (-63.22°F) or lower, DTC B1412 may be output even though the system is normal.