The ambient temperature senor located at the center stay of the condensor detects ambient air temperature. It is a negative type thermistor whose resistance is inversely proportional to temperature. Its output is used for discharge temperature sensor, sensor fail-safe, temperature regulation door lock, blower motor level control, mix mode control and in-car humidity control
The ECM sets DTC B1238 if there is an open circuit in ambient temp sensor signal harness or the measured resistance value of sensor is more than threshold value(about 507㏀)
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Voltage check | ● Open Circuit in harness ● Fault ambient temp.sensor ● Fault A/C Control Unit |
Threshold value | ● > 4.9V | |
Detecting time | ● 0.3sec | |
FAIL SAFE | ● Control with the vlaue of 20℃(67℉) |
Temperature(℃) | Resistance(㏀) | Temperature(℃) | Resistance(㏀) |
-30 | 507 | 25 | 30 |
-15 | 215.3 | 35 | 24.2 |
0 | 97.5 | 60 | 16 |
15 | 59.6 | 80 | 10.8 |
