Operation CHARM: Car repair manuals for everyone.

General Information





Component Location





General Description

The Evaporator sensor located on 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

DTC Description

The ECM sets DTC B1242 if there is an open circuit in evaporator sensor signal harness or the measured resistance value of the sensor is more than the threshold value (about 13.6 Kohms)

DTC Detecting Condition





Schematic Diagram





Signal Waveform

** Resistance value of evaporator sensor as a function of temperature.