B257B

B257B, B257C AMBIENT SENSOR





Description

COMPONENT DESCRIPTION

Ambient Sensor
The ambient sensor (1) is attached on the radiator core support (left side). It detects ambient temperature and converts it into a resistance value which is then input into the auto amp.






Ambient Sensor Circuit






AMBIENT TEMPERATURE INPUT PROCESS
The auto amp. includes a processing circuit for the ambient sensor input. However, when the temperature detected by the ambient sensor increases quickly, the processing circuit retards the auto amp. function. It only allows the auto amp. to recognize an ambient temperature increase of 0.33�C (0.6�F) per 100 seconds.
As an example, consider stopping for a few minutes after high speed driving. Although the actual ambient temperature has not changed, the temperature detected by the ambient sensor will increase. This is because the heat from the engine compartment can radiate to the front bumper area, location of the ambient sensor.




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 AMBIENT SENSOR AND GROUND
1. Disconnect ambient sensor connector.
2. Turn ignition switch ON.
3. Check voltage between ambient sensor harness connector E211 terminal 1 and ground.





Is the inspection result normal?
YES - GO TO 2.
NO - GO TO 4.
2.CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND AUTO AMP.
1. Turn ignition switch OFF.
2. Disconnect auto amp. connector.
3. Check continuity between ambient sensor harness connector E211 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 AMBIENT SENSOR
Refer to "Component Inspection".
Is the inspection result normal?
YES - Replace auto amp. Refer to Service and Repair.
NO - Replace ambient sensor. Refer to Service and Repair.
4.CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND AUTO AMP.
1. Turn ignition switch OFF.
2. Disconnect auto amp. connector.
3. Check continuity between ambient sensor harness connector E211 terminal 1 and auto amp. harness connector M37 terminal 28.





4. Check continuity between ambient sensor harness connector E211 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 ambient sensor (1) connector E211, measure resistance between terminals 1 and 2 at sensor side. Refer to table below.






If NG, replace ambient sensor. Refer to Service and Repair.