B257B

B257B, B257C AMBIENT SENSOR





DTC Logic

DTC DETECTION LOGIC

NOTE:
- If DTC is displayed along with DTC U1000, first perform the trouble diagnosis for DTC U1000. HAC-
50, "DTC Logic".
- If DTC is displayed along with DTC U1010, first perform the trouble diagnosis for DTC U1010. Control Unit Control Unit Control Unit, "DTC Logic".






DTC CONFIRMATION PROCEDURE
1.PERFORM DTC CONFIRMATION PROCEDURE
With CONSULT-III
1. Turn ignition switch ON.
2. Select "Self Diagnostic Result" mode of "HVAC" using CONSULT-III.
3. Check DTC.
Is DTC detected?
YES - SEE Diagnosis Procedure.
NO - INSPECTION END




Diagnosis Procedure
1.CHECK AMBIENT SENSOR POWER SUPPLY
1. Turn ignition switch OFF.
2. Disconnect ambient sensor connector.
3. Turn ignition switch ON.
4. Check voltage between ambient sensor harness connector and ground.





Is the inspection result normal?
YES - GO TO 2.
NO - GO TO 4.
2.CHECK AMBIENT SENSOR GROUND CIRCUIT FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect A/C auto amp. connector.
3. Check continuity between ambient sensor harness connector and A/C auto amp harness connector.





Is the inspection result normal?
YES - GO TO 3.
NO - Repair harness or connector.
3.CHECK AMBIENT SENSOR
Check ambient sensor. SEE Component Inspection.
Is the inspection result normal?
YES - Replace A/C auto amp. Automatic Air Conditioner.
NO - Replace ambient sensor. Service and Repair.
4.CHECK AMBIENT SENSOR POWER SUPPLY CIRCUIT FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect A/C auto amp. connector.
3. Check continuity between ambient sensor harness connector and A/C auto amp. harness connector.





Is the inspection result normal?
YES - GO TO 5.
NO - Repair harness or connector.
5.CHECK AMBIENT SENSOR POWER SUPPLY CIRCUIT FOR SHORT
Check continuity between ambient sensor harness connector and ground.





Is the inspection result normal?
YES - Replace A/C auto amp. Automatic Air Conditioner.
NO - Repair harness or connector.




Component Inspection
1.CHECK AMBIENT SENSOR
1. Remove ambient sensor. Service and Repair.
2. Check resistance between ambient sensor terminals. Refer to applicable table for the normal value.





Is the inspection result normal?
YES - INSPECTION END
NO - Replace ambient sensor. Service and Repair.