The ambient temperature sensor is located at the center stay of the condensor and detects ambient air temperature. It is a negative type thermistor whose resistance is inversely proportional to the 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.
DTC B1238 sets if Ambient Temperature sensor signal is at or over 4.9V for 0.3 seconds.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Voltage check | 1. Poor Connection in harness 2. Open in signal circuit 3. Shrot to battery in signal circuit 4. Faulty Ambient Temperature sensor 5. Faulty air condtioner control Module |
Enable Conditions |
•
Ignition ON | |
Threshold value |
•
Ambient Temperature sensor signal is at or over 4.9V for 0.3 seconds | |
Failsafe |
•
Displayed '--' and A/C control Module regards and controls it as 20℃(68℉) |
※ Resistance value of ambient temp.sensor as a function of temperature.
Temperature(℃/℉) | Resistance(㏀) | Temperature(℃/℉) | Resistance(㏀) |
-20/-4 | 271.4 | 50/122 | 11 |
0/32 | 95.1 | 60/140 | 7.58 |
25/77 | 30 |
