The Evaporator sensor located on the HVAC unit and detects the evaporator core temperature. It is a negative type thermistor whose resistance is inversely proportional to temperature. The Evaporator sensor converts the measured temperature into a voltage value and delivers it to A/C ECU. When core temperature is blow threshold value, A/C ECU interrupts compressor relay power, in order to prevent evaporator freezing by excessive cooling.
DTC B1241 sets if the Evaporator Sensor signal is at or below 0.1V for 0.3 seconds.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Voltage check | 1. Short circuit in harness 2. Faulty Evaporator sensor 3. Faulty A/C Control Unit |
Enable Conditions |
•
Ignition ON | |
Threshold value |
•
Evaporator Sensor signal is at or below 0.1V for 0.3 seconds. | |
Failsafe |
•
Control with the value of -2℃(28.4℉) |
※ Resistance value of evaporator sensor as a function of temperature.
Temperature(℃/℉) | Resistance(㏀) | Temperature(℃/℉) | Resistance(㏀) |
-10/-14 | 43.3 | 20/68 | 12.1 |
0/32 | 27.6 | 30/86 | 8.3 |
10/50 | 18 | 40/104 | 5.8 |
