The ambient temperature sensor located at the center stay of the condensor detects ambient air temperature. It is joined to AQS sensor as one boby. It is a negative type thermistor whose resistance is inversely proportional to temperature. Its output is used for sensor fail-safe, temperature regulation door lock, blower motor level control, mix mode control and in-car humidity control.
The ECM sets DTC B1237 if there is a short circuit in ambient temp sensor signal harness or the measured voltage value of the sensor is less than the threshold value(0.1V)
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Voltage check | ● Short circuit in harness ● Faulty ambient temp.sensor ● Faulty A/C Control Unit |
Threshold value | ●< 0.1V | |
Detecting time | ● 0.3sec | |
FAIL SAFE | ● Control with the value of 20℃ |
※ Resistance value of ambient temp.sensor as a function of temperature.
Temperature(℃) | Resistance(㏀) | Temperature(℃) | Resistance(㏀) |
-20 | 271.1 | 50 | 10.9 |
0 | 95.1 | 60 | 7.5 |
25 | 30.0 | ||
