B1412

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: B1412: Ambient Temperature Sensor Circuit
B1412 - Ambient Temperature Sensor Circuit

DESCRIPTION

The ambient temperature sensor is installed in front of the condenser. This sensor detects the temperature outside the cabin and sends the appropriate signals to the A/C amplifier via the CAN communication system.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK CAN COMMUNICATION SYSTEM

(a) Use the Techstream to check if the CAN communication system is functioning normally.

Result:





B -- GO TO CAN COMMUNICATION SYSTEM How to Proceed With Troubleshooting
A -- Continue to next step.

2. READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Body / Air Conditioner / Data List.

(e) Measure the resistance according to the value(s) in the table below.

Air Conditioner





OK:

The display is as specified in the normal condition column.

Result:





B -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures

C -- REPLACE AIR CONDITIONING AMPLIFIER Removal
A -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (AMBIENT TEMPERATURE SENSOR CIRCUIT)

(a) Disconnect the connector from the combination meter.





(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





Text in Illustration





NG -- INSPECT AMBIENT TEMPERATURE SENSOR
OK -- Continue to next step.

4. INSPECT COMBINATION METER

(a) Temporarily replace the combination meter with a known good one Removal.

HINT
Since the combination meter cannot be inspected while it is removed from the vehicle, replace the combination meter with a known good one and check that the condition returns to normal.

(b) Check for DTCs.

Result:





B -- REPLACE AIR CONDITIONING AMPLIFIER Removal

A -- REPLACE COMBINATION METER Removal

5. INSPECT AMBIENT TEMPERATURE SENSOR

(a) Remove the ambient temperature sensor.





(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NOTICE:
* Hold the sensor only by its connector. Touching the sensor may change the resistance value.
* When measuring, the sensor temperature must be the same as the ambient temperature.

HINT
As the temperature increases, the resistance decreases (see the graph).

Text in Illustration





NG -- REPLACE AMBIENT TEMPERATURE SENSOR Removal

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (AMBIENT TEMPERATURE SENSOR - COMBINATION METER)