Automatic Air Conditioning

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System): B1412/12: Ambient Temperature Sensor Circuit
B1412/12 - Ambient Temperature Sensor Circuit

DESCRIPTION

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 (COMBINATION METER - A/C AMPLIFIER)

(a) Use the Techstream.

(b) Check that the CAN communication system functions normally between the combination meter and the A/C amplifier.

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 and turn the Techstream main switch on.

(c) Select the item below in the Data List, and read the display on the Techstream.

Data List / Air Conditioner

Data List / Air Conditioner:

OK:

The display is as specified in the "Normal Condition" column.

Result:





C -- REPLACE AIR CONDITIONING AMPLIFIER Removal

B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE Air Conditioning System (For Automatic Air Conditioning System)
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:





HINT
As the temperature increases, the resistance decreases.

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

4. REPLACE COMBINATION METER

(a) Replace the combination meter 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 -- END

5. INSPECT AMBIENT TEMPERATURE SENSOR

(a) Remove the ambient temperature sensor.

(b) Disconnect the connector from the ambient temperature sensor.





(c) 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).

NG -- REPLACE AMBIENT TEMPERATURE SENSOR Removal

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