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 and cooling unit assembly. It produces vacuum pressure due to air discharged from the heater and 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 Reading and Clearing Diagnostic Trouble Codes and perform self-diagnosis STEP-2.
Confirm that code No. 20 is displayed.
NG - 1. Replace in-vehicle 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 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 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

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.