The Evaporator sensor is located on the AC/heater boxand it detects the evaporator core temperature. When the core temperature is below the threshold value, the A/C ECU interrupts the compressor relay in order to prevent evaporator freezing.
DTC B1242 sets if Evaporator sensor signal is at or over 4.9V for 0.3 seconds.
Item
Detecting Condition
DTC Strategy
Voltage check
Open in signal circuit
Short to battery in signal circuit
Faulty Evaporator sensor
Faulty Air conditioner control Unit
Enable Conditions
Ignition ON
Threshold value
Evaporator sensor signal is at or over 4.9V 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(?)
-25/14
43.3
20/68
12.1
0/32
27.6
30/86
8.3
10/50
18
40/104
5.8