B257C
B257B, B257C AMBIENT SENSORDescription
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
Step 1-2:
Diagnosis Procedure
Step 1-4:
Step 4 (Continued):
Component Inspection
After disconnecting ambient sensor (1) connector E211, measure resistance between terminals 1 and 2 at sensor side. Refer to table given.
If NG, replace ambient sensor.