B2578

B2578, B2579 IN-VEHICLE SENSOR





Description
In-vehicle Sensor






The in-vehicle sensor (1) is located on instrument lower cover. It converts variations in temperature of compartment air drawn from the aspirator into a resistance value. It is then input into the auto etc.

In-vehicle Sensor Circuit






Aspirator
The aspirator (1) 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.







Arrow indicates Vehicle front











DTC Logic

DTC DETECTION LOGIC






DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at least 10 seconds before conducting the next test.
- GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON and wait at least 5 seconds.
2. Check DTC.
Is DTC detected?
YES - Go to Diagnosis Procedure. "Diagnosis Procedure".
NO - END.




Diagnosis Procedure
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 M34 terminal 1 and ground.





Is the inspection result normal?
YES - GO TO 2.
NO - GO TO 4.
2.CHECK CIRCUIT CONTINUITY BETWEEN IN-VEHICLE SENSOR AND AUTO AMP.
1. Turn ignition switch OFF.
2. Disconnect auto amp. connector.
3. Check continuity between in-vehicle sensor harness connector M34 terminal 2 and auto amp. harness connector M37 terminal 26.





Is the inspection result normal?
YES - GO TO 3.
NO - Repair harness or connector.
3.CHECK IN-VEHICLE SENSOR
Refer to "Component Inspection".
Is the inspection result normal?
YES - Replace auto amp. Refer to Service and Repair.
NO - Replace in-vehicle sensor. Refer to In-Vehicle Sensor.
4.CHECK CIRCUIT CONTINUITY BETWEEN IN-VEHICLE SENSOR AND AUTO AMP.
1. Turn ignition switch OFF.
2. Disconnect auto amp. connector.
3. Check continuity between in-vehicle sensor harness connector M34 terminal 1 and auto amp. harness connector M37 terminal 27.





4. Check continuity between in-vehicle sensor harness connector M34 terminal 1 and ground.





Is the inspection result normal?
YES - Replace auto amp. Refer to Service and Repair.
NO - Repair harness or connector.




Component Inspection




After disconnecting in-vehicle sensor (1) connector M34, measure resistance between terminals 1 and 2 at sensor side. Refer to table below.






If NG, replace in-vehicle sensor. Refer to In-Vehicle Sensor