In-Vehicle Sensor Circuit

TROUBLE DIAGNOSIS


In-vehicle Sensor Circuit


COMPONENT DESCRIPTION

In-vehicle Sensor





The in-vehicle sensor is located on instrument driver lower panel. It converts variations in temperature of compartment air drawn from the aspirator into a resistance value. It is then input into the unified meter and A/C amp.

Aspirator





The aspirator is located on driver's side of heater & cooling unit assembly. It produces vacuum pressure due to air discharged from the heater & cooling unit assembly, continuously taking compartment air in the aspirator.

In-vehicle Sensor Circuit

DIAGNOSIS PROCEDURE FOR IN-VEHICLE SENSOR





SYMPTOM: In-vehicle sensor circuit is open or shorted. (22 or -22 is indicated on unified meter and A/C amp. as a result of performing self-diagnosis STEP-2.)





1.CHECK VOLTAGE BETWEEN IN-VEHICLE SENSOR AND GROUND
1. Disconnect in-vehicle sensor connector.
2. Turn ignition switch ON.





3. Check voltage between in-vehicle sensor harness connector
M54 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 IN-VEHICLE 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 in-vehicle sensor harness connector
M54 terminal 2 and unified meter and A/C amp. harness connector M65 terminal 60.

2 - 60: Continuity should exist.

OK or NG
OK - GO TO 3.
NG - Repair harness or connector.
3.CHECK IN-VEHICLE SENSOR
Refer to "COMPONENT INSPECTION (In-vehicle 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 in-vehicle 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 IN-VEHICLE 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 in-vehicle sensor harness connector
M54 terminal 1 and unified meter and A/C amp. harness connector M65 terminal 44.

1 - 44: Continuity should exist.

4. Check continuity between in-vehicle sensor harness connector
M54 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

In-vehicle Sensor





After disconnecting in-vehicle sensor connector M54, measure resistance between terminals 1 and 2 at sensor side. Refer to the table below.





If NG, replace in-vehicle sensor.