Operation CHARM: Car repair manuals for everyone.

In-Vehicle Sensor Circuit

COMPONENT DESCRIPTION






In-vehicle sensor
The in-vehicle sensor is located on instrument lower panel. It converts variations in temperature of compartment air drawn from the aspirator into a resistance value. It is then input into the auto amplifier.









Aspirator
The aspirator is located in front of heater unit. It produces vacuum pressure due to air discharged from the heater unit, continuously taking compartment air in the aspirator.

DIAGNOSTIC PROCEDURE





Step 1 - 2:




Step 3 - 4:






SYMPTOM:
* In-vehicle sensor circuit is open or shorted. (22 or -22 is indicated on the display as a result of conducting Self-diagnosis STEP 2.)

Step-By-Step Procedure


COMPONENT INSPECTION








In-vehicle Sensor
After disconnecting in-vehicle sensor harness connector, measure resistance between terminals 1 and 2 at sensor harness side, using the table above.

If NG, replace in-vehicle sensor.