Sunload Sensor Circuit

TROUBLE DIAGNOSIS


Sunload Sensor Circuit


COMPONENT DESCRIPTION

Sunload Sensor





The sunload sensor is located on the driver's side front defroster grille. It detects sunload entering through windshield by means of a photo diode. The sensor converts the sunload into a current value which is then input into the unified meter and A/C amp.

Sunload Sensor Circuit

SUNLOAD INPUT PROCESS





- The unified meter and A/C amp. also includes a processing circuit which averages the variations in detected sunload over a period of time. This prevents drastic swings in the ATC system operation due to small or quick variations in detected sunload.
- For example, consider driving along a road bordered by an occasional group of large trees. The sunload detected by the sunload sensor will vary whenever the trees obstruct the sunlight. The processing circuit averages the detected sunload over a period of time, so that the (insignificant) effect of the trees momentarily obstructing the sunlight does not cause any change in the ATC system operation. On the other hand, shortly after entering a long tunnel, the system will recognize the change in sunload, and the system will react accordingly.

DIAGNOSIS PROCEDURE FOR SUNLOAD SENSOR
SYMPTOM: Sunload sensor circuit is open or shorted. (25 or -25 is indicated on unified meter and A/C amp. as a result of performing self-diagnosis STEP-2.)
1.CHECK VOLTAGE BETWEEN SUNLOAD SENSOR AND GROUND
1. Disconnect sunload sensor connector.
2. Turn ignition switch ON.





3. Check voltage between sunload sensor harness connector M87 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 SUNLOAD 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 sunload sensor harness connector
M87 terminal 2 and unified meter and A/C amp. harness connector M65 terminal 62.

2 - 62: Continuity should exist.

OK or NG
OK - GO TO 3.
NG - Repair harness or connector.
3.CHECK SUNLOAD SENSOR
1. Reconnect sunload sensor connector and unified meter and A/C amp. connector.
2. Refer to "COMPONENT INSPECTION (Sunload Sensor)".
OK or NG
OK - 1. Replace unified meter and A/C amp.
2. Go to self-diagnosis Self-Diagnosis Function and perform self-diagnosis STEP-2.
Confirm that code No. 20 is displayed.
NG - 1. Replace sunload sensor.
2. Go to self-diagnosis Self-Diagnosis Function and perform self-diagnosis STEP-2.
Confirm that code No. 20 is displayed.
4.CHECK CIRCUIT CONTINUITY BETWEEN SUNLOAD 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 sunload sensor harness connector
M87 terminal 1 and unified meter and A/C amp. harness connector M65 terminal 46.

1 - 46: Continuity should exist.

4. Check continuity between sunload sensor harness connector
M87 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 Self-Diagnosis Function and perform self-diagnosis STEP-2.
Confirm that code No. 20 is displayed.
NG - Repair harness or connector.

COMPONENT INSPECTION

Sunload Sensor





Measure voltage between unified meter and A/C amp. harness connector M65 terminal 46 and ground.
- When checking sunload sensor, select a place where sunshine directly on it.





If NG, replace sunload sensor.