Ambient Sensor Circuit

Ambient Sensor Circuit

COMPONENT DESCRIPTION




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

AMBIENT TEMPERATURE INPUT PROCESS
The front air control 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 front air control function. It only allows the front air control to recognize an ambient temperature increase of 0.33 °C (0.6 °F) per 100 seconds.

This prevents constant adjustments due to momentary conditions, such as stopping 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 grille area, location of the ambient sensor.

Step 1-2:

Step 3-6:

Step 7-9:

DIAGNOSTIC PROCEDURE FOR AMBIENT SENSOR
SYMPTOM: Ambient sensor circuit is open or shorted. Using the CONSULT-II, DTC B257B or B257C is displayed. Without a CONSULT-II, code 40 or 41 is indicated on front air control as a result of conducting the front air control self-diagnosis.

COMPONENT INSPECTION




Ambient Sensor
After disconnecting ambient sensor (1) connector E1, measure resistance between terminals 1 and 2 at sensor component side, using the table above.
If NG, replace ambient sensor.