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Home >> Lexus >> 2020 >> UX 200 Luxury >> Repair and Diagnosis >> External Pages >> Different car >> Section 60 (Air Conditioning System - Diagnostic Codes (1 Of 2) (Hybrid)) >> AIR CONDITIONING SYSTEM (for HV Model) >> DTC B1412: Ambient Temperature Sensor Circuit [10/2018 - ] >> Description

DTC B1412: Ambient Temperature Sensor Circuit [10/2018 - ]: Description

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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. 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. As the temperature increases, the resistance decreases.

The air conditioning amplifier assembly applies voltage (5 V) to the thermistor assembly and reads voltage changes due to changes in the resistance of the thermistor assembly.

DTC No. Detection Item DTC Detection Condition Trouble Area Memory
B1412 Ambient Temperature Sensor Circuit
  • Open in ambient temperature sensor circuit
  • Short in ambient temperature sensor circuit
  • Thermistor assembly
  • Air conditioning amplifier assembly
  • Harness or connector
Memorized
(4 sec. or more)*
  1. *: The air conditioning amplifier assembly stores this DTC if the malfunction has occurred for the period of time indicated in the brackets.

DTC Detection Conditions

  Vehicle Condition 
Pattern 1  Pattern 2 
Diagnosis Condition Power switch on (IG) ◦  ◦ 
Malfunction Status Open in ambient temperature sensor circuit ◦ 
Short in ambient temperature sensor circuit ◦ 
Detection Time 4 sec. or more  4 sec. or more 
Number of Trips 1 trip  1 trip 

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