Ambient Sensor With 7 Inch Display

B257B, B257C AMBIENT SENSOR





Description

AMBIENT SENSOR





- The ambient sensor (1) is installed to the hood lock stay.
- The ambient sensor converts the ambient temperature detected with thermistor into the voltage, and the A/C auto amp. inputs this voltage.

AMBIENT TEMPERATURE CORRECTION
- The A/C auto amp. inputs the temperature detected with the ambient sensor as the ambient temperature.
- Perform the correction of the temperature detected with the ambient sensor for air conditioning control and for ambient temperature display.
- Since the engine heat influences on the ambient sensor during idling condition, the A/C auto amp. retards the ambient temperature indication of the combination meter to avoid the effect of steep temperature change.
- Select and use the initial value of ambient temperature data depending on the coolant temperature when turning the ignition switch from OFF to ON. Use the detection temperature of the ambient sensor at low coolant temperature [less than approximately 56�C (133�F)]. Use the memory data (before the ignition switch is
OFF) when the engine is warming up [approximately 56�C (133�F) or more].
- Do not perform the correction of the ambient temperature when the detection temperature of the ambient temperature is less than approximately -29�C (-20�F) (for ambient temperature display) or less than approximately -20�C (-4�F) (for air conditioning control).

SET TEMPERATURE CORRECTION
The A/C auto amp. performs the correction to the target temperature set by the temperature control dial so as to match the temperature felt by the passengers depending on the ambient temperature detected with the ambient sensor and controls it so that the interior air temperature is always the most suitable.




DTC Logic

DTC DETECTION LOGIC






DTC CONFIRMATION PROCEDURE
1.PERFORM SELF-DIAGNOSIS
With CONSULT-III
1. Perform the "SELF-DIAGNOSIS".
2. Check if any DTC is detected in the self-diagnostic results.

NOTE:
- If DTC is displayed along with DTC "U1000" or "U1010", first diagnose the DTC "U1000" or "U1010". Climate Control With 7 Inch Display or Climate Control With 7 Inch Display.
- If there is an open circuit in the ambient sensor, A/C auto amp registers extreme cold [-30�C (-22�F)] and adjusts the temperature control warmer.
Is DTC "B257B" or "B257C" displayed?
YES - Perform the diagnosis for the ambient sensor. SEE Diagnosis Procedure.
NO - INSPECTION END




Diagnosis Procedure
1.CHECK AMBIENT SENSOR POWER SUPPLY CIRCUIT
1. Turn the ignition switch OFF.
2. Disconnect ambient sensor connector.
3. Turn the 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 CIRCUIT CONTINUITY
1. Turn the ignition switch OFF.
2. Disconnect the A/C auto amp. connector.
3. Check for continuity between the ambient sensor harness connector and A/C auto amp harness connector.





Is the inspection result normal?
YES - GO TO 3.
NO - Repair the harnesses or connectors.
3.CHECK AMBIENT SENSOR
Check the ambient sensor components. SEE Component Inspection.
Is the inspection result normal?
YES - Replace the A/C auto amp.
NO - Replace the ambient sensor.
4.CHECK AMBIENT SENSOR CIRCUIT CONTINUITY
1. Turn the ignition switch OFF.
2. Disconnect the A/C auto amp. connector.
3. Check for continuity between the ambient sensor harness connector and A/C auto amp. harness connector.





4. Check for continuity between ambient sensor harness connector and ground.





Is the inspection result normal?
YES - Replace the A/C auto amp.
NO - Repair the harnesses or connectors.




Component Inspection
1.CHECK AMBIENT SENSOR
1. Turn the ignition switch OFF.
2. Remove the ambient sensor. Exploded View With 7 Inch Display.
3. Check the resistance between the ambient sensor terminals. Refer to the applicable table for the normal value.





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