Air Conditioning System

AIR CONDITIONING: AIR CONDITIONING SYSTEM: B1412/12: Ambient Temperature Sensor Circuit

DTC B1412/12 - Ambient Temperature Sensor Circuit

DESCRIPTION

This sensor detects the temperature outside the cabin and sends appropriate signals to the ECM.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM (AMBIENT TEMPERATURE SENSOR)
(a) Check the Data List for proper functioning of the ambient temperature sensor.

Air Conditioner





OK:
The display is as specified in the normal condition.

Result





C -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- Continue to next step.
2. CHECK ECM (TAM - E 2 VOLTAGE)




(a) Remove the ECM but do not disconnect the connector.
(b) Turn the ignition switch ON.
(c) Measure the voltage of the connector.
Standard voltage:





HINT: As the temperature increases, the voltage decreases.

Result





C -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- Continue to next step.
3. INSPECT COOLER THERMISTOR (AMBIENT TEMPERATURE SENSOR)




(a) Remove the cooler thermistor.
(b) Measure the resistance of the thermistor.
Standard resistance:





HINT: As the temperature increases, the resistance decreases.

NG -- REPLACE COOLER THERMISTOR (AMBIENT TEMPERATURE SENSOR)
OK -- Continue to next step.
4. CHECK WIRE HARNESS (COOLER THERMISTOR (AMBIENT TEMPERATURE SENSOR) - ECM)




(a) Disconnect the A1 thermistor connector.
(b) Disconnect the E2 and E6 ECM connectors.
(c) Measure the resistance of the wire harness side connector.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM