Automatic Air Conditioning

AMBIENT SENSOR

Component Description


COMPONENT DESCRIPTION

Ambient Sensor





The ambient sensor (1) is attached on the radiator core support (left side). It detects ambient temperature and converts it into a value which is then input into the front air control.

AMBIENT TEMPERATURE INPUT PROCESS

The front air control 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.
This prevents constant adjustments due to momentary conditions, such as stopping 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.


Ambient Sensor Diagnosis Procedure

Regarding Wiring Diagram information, Automatic Air Conditioning.

DIAGNOSTIC PROCEDURE FOR AMBIENT SENSOR






SYMPTOM: Ambient sensor circuit is open or shorted. Using the
CONSULT, DTC B257B or B257C is displayed. Without CONSULT, code 40 or 41 is indicated on front air control as a result of conducting the front air control self-diagnosis.

1. CHECK VOLTAGE BETWEEN AMBIENT SENSOR AND GROUND






1.Disconnect ambient sensor connector.
2.Turn ignition switch ON.
3.Check voltage between ambient sensor harness connector E1
terminal 1 and ground.
1 - Ground: Approx. 5V
Is the inspection result normal?
YES- GO TO 2.
NO- GO TO 4.

2. CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND FRONT AIR CONTROL






1.Turn ignition switch OFF.
2.Disconnect front air control connector.
3.Check continuity between ambient sensor harness connector
E1 (B) terminal 2 and front air control harness connector M49
(A) terminal 26.
2 - 26: Continuity should exist.
Is the inspection result normal?
YES- GO TO 3.
NO- Repair harness or connector.

3. CHECK AMBIENT SENSOR

Check the ambient sensor circuit. .
Is the inspection result normal?
YES- 1.Replace front air control. Service and Repair.
2.GO TO Front Air Control Self-Diagnosis and perform self-diagnosis.
NO- 1.Replace ambient sensor. Service and Repair.
2.GO TO Front Air Control Self-Diagnosis and perform self-diagnosis.

4. CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND FRONT AIR CONTROL






1.Turn ignition switch OFF.
2.Disconnect front air control connector.
3.Check continuity between ambient sensor harness connector
E1 (B) terminal 1 and front air control harness connector M49
(A) terminal 25.
1 - 25: Continuity should exist.
4.Check continuity between ambient sensor harness connector
E1 (B) terminal 2 and ground.
1 - Ground: Continuity should not exist.
Is the inspection result normal?
YES- 1.Replace front air control. Service and Repair.
2.GO TO Front Air Control Self-Diagnosis and perform self-diagnosis.
NO- Repair harness or connector.


Ambient Sensor Component Inspection


COMPONENT INSPECTION

Ambient Sensor





After disconnecting ambient sensor (1) connector E1, measure resistance between terminals 1 and 2 at sensor component side, using the table below.





If NG, replace ambient sensor. Service and Repair.