Ambient Sensor

TROUBLE DIAGNOSIS


Ambient Sensor Circuit


COMPONENT DESCRIPTION

Ambient Sensor
The ambient sensor is attached on the radiator core support (left side). It detects ambient temperature and converts it into a resistance value which is then input into the unified meter and A/C amp.






Ambient Sensor Circuit






AMBIENT TEMPERATURE INPUT PROCESS
- The unified meter and A/C amp. 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 unified meter and A/C amp. function. It only allows the unified meter and A/C amp. to recognize an ambient temperature increase of 0.33�C (0.6�F) per 100 seconds.





- As an example, consider stopping for a few minutes 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 bumper area, location of the ambient sensor.

DIAGNOSIS PROCEDURE FOR AMBIENT SENSOR
SYMPTOM: Ambient sensor circuit is open or shorted. (21 or -21 is indicated on unified meter and A/C amp. as a result of performing self-diagnosis STEP-2.)
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 E62 terminal 1 and ground.

1 - Ground : Approx. 5 V

OK or NG
OK - GO TO 2.
NG - GO TO 4.
2.CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect unified meter and A/C amp. connector.





3. Check continuity between ambient sensor harness connector
E62 terminal 2 and unified meter and A/C amp. harness connector M65 terminal 61.

2 - 61 : Continuity should exist.

OK or NG
OK - GO TO 3.
NG - Repair harness or connector.
3.CHECK AMBIENT SENSOR
Refer to "COMPONENT INSPECTION (Ambient Sensor)".
OK or NG
OK - 1. Replace unified meter and A/C amp.
2. Go to self-diagnosis Reading and Clearing Diagnostic Trouble Codes and perform self-diagnosis STEP-2.
Confirm that code No. 20 is displayed.
NG - 1. Replace ambient sensor.
2. Go to self-diagnosis Reading and Clearing Diagnostic Trouble Codes and perform self-diagnosis STEP-2.
Confirm that code No. 20 is displayed.
4.CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect unified meter and A/C amp. connector.





3. Check continuity between ambient sensor harness connector
E62 terminal 1 and unified meter and A/C amp. harness connector M65 terminal 45.

1 - 45 : Continuity should exist.

4. Check continuity between ambient sensor harness connector
E62 terminal 1 and ground.

1 - Ground : Continuity should not exist.

OK or NG
OK - 1. Replace unified meter and A/C amp.
2. Go to self-diagnosis Reading and Clearing Diagnostic Trouble Codes and perform self-diagnosis STEP-2.
Confirm that code No. 20 is displayed.
NG - Repair harness or connector.

COMPONENT INSPECTION

Ambient Sensor
After disconnecting ambient sensor connector E62, measure resistance between terminals 1 and 2 at sensor side. Refer to the table below.










If NG, replace ambient sensor.