The Evaporator sensor located at heater unit detects the core temperature and interrupts compressor relay power, in order to prevent evaporator freezing by excessive cooling. It is a negative type thermistor whose resistance is inversely proportional to temperature
The ECM sets DTC B1242 if there is an open circuit in evaporator sensor signal harness or the measured resistance value of sensor is more than threshold value(about 13.6㏀)
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Voltage check | ● Open Circuit in harness ● Fault Evaporator sensor ● Fault A/C Control Unit |
Threshold value | ● > 4.9V | |
Detecting time | ● 0.3sec | |
FAIL SAFE | ● Control with the vlaue of -2℃ |
Temperature(℃) | Resistance(㏀) | Temperature(℃) | Resistance(㏀) |
-10 | 13.6 | 15 | 3.9 |
0 | 8 | 30 | 2 |
5 | 6.2 | 40 | 1.3 |
10 | 4.9 | 50 | 0.9 |
