Humidity sensor located at heater control unit detects in-car humidity for in-car humidity control. Humidity sensor and incar sensor are joined as one body.
Humidity sensor transforms measured humidity into frequency value and delivers it to A/C Control unit. If ambient air temperature or in-car humidity is in a specified range that can makes frost on the windowglass, A/C will be activated to control in-car humidity to prevent frost on the windowglass.
The ECM sets DTC B1200 if there is an open circuit or poor connection of connected part in humidity sensor signal harness.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Voltage check | ● Open Circuit in signal harness. ● Faulty Humidity Sensor ● Faulty A/C control unit |
Threshold value | ● > 4.9V | |
Detecting time | ● 10msec | |
FAIL SAFE | ● Control with the value of 10% |
※ Frequency value of humidity sensor as a function of humidity.
Humidity(%) | Frequency(Hz) | Humidity(%) | Frequency(Hz) |
0 | 7351 | 60 | 6600 |
10 | 7224 | 70 | 6468 |
20 | 7100 | 80 | 6330 |
30 | 6976 | 90 | 6186 |
40 | 6853 | 100 | 6033 |
50 | 6728 | ||
