Ambient Temperature Sensor / Switch HVAC: Testing and Inspection

AMBIENT SENSOR





Description

COMPONENT DESCRIPTION

Ambient Sensor





The ambient sensor (1) (sedan location shown, coupe location similar) is attached on the front bumper reinforcement. It detects ambient temperature and converts it into a resistance value which is then input into the front air control.

AMBIENT TEMPERATURE INPUT PROCESS
The automatic amplifier includes a processing circuit for the ambient sensor input. However, when the temperature detected by the ambient sensor increases quickly, the processing circuit retards the front air control function. It only allows the front air control to recognize an ambient temperature increase of 0.33�C (0.6�F) per 100 seconds.
As an example, consider stopping for a cup of coffee after high speed driving. Although the actual ambient temperature has not changed, the temperature detected by the ambient sensor will increase. This is because the heat from the engine compartment can radiate to the front grille area, location of the ambient sensor.




Diagnosis Procedure
Regarding Wiring Diagram information, Air Conditioner Control Coupe Automatic Air Conditioner or Air Conditioner Control Sedan Automatic Air Conditioner.

DIAGNOSIS PROCEDURE FOR AMBIENT SENSOR





SYMPTOM: Ambient sensor circuit is open or shorted.
1.CHECK VOLTAGE BETWEEN AMBIENT SENSOR HARNESS CONNECTOR AND BODY GROUND





1. Disconnect ambient sensor connector.
2. Press ignition switch ON.
3. Check voltage between ambient sensor harness connector
E211 terminal 1 and ground.





Is the inspection result normal?
YES - GO TO 2
NO - GO TO 4
2.CHECK AMBIENT SENSOR GROUND CIRCUIT BETWEEN AMBIENT SENSOR AND IPDM E/R





1. Press ignition switch OFF.
2. Disconnect IPDM E/R connector E201.
3. Check continuity between IPDM E/R harness connector M201
(A) terminal 99 and ambient sensor harness connector E211 (B) terminal 2.





If OK, check harness for short.
Is the inspection result normal?
YES - GO TO 3
NO - Repair harness or connector.
3.CHECK AMBIENT SENSOR
Check ambient sensor. Ambient Sensor
Is the inspection result normal?
YES - 1. Replace front air control. Service and Repair.
2. Confirm system operation.
NO - Replace ambient sensor. Service and Repair.
4.CHECK AMBIENT SENSOR CIRCUIT BETWEEN AMBIENT SENSOR AND IPDM E/R





1. Press ignition switch OFF.
2. Disconnect IPDM E/R connector E201.
3. Check continuity between IPDM E/R harness connector E201
(A) terminal 100 and ambient sensor harness connector E211
(B) terminal 1.





If OK, check harness for short.
Is the inspection result normal?
YES - 1. Replace IPDM E/R. Service and Repair.
2. Confirm system operation.
NO - Repair harness or connector.




Component Inspection

Ambient Sensor





After disconnecting ambient sensor (1) harness connector E211, measure resistance between terminals 2 and 1 at sensor side, using the table below.





If NG, replace ambient sensor. Service and Repair.