Powertrain, generic

P0EC2 A/C Refrigerant Temperature Sensor B Circuit High

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

With P0EC2 the signal of refrigerant temperature sensor B is stuck near the reference voltage. An NTC thermistor would only get there at extreme cold, so an open circuit somewhere in the loop is far more likely. No manufacturer documents P0EC2 publicly. Mitsubishi's procedure for the analogous evaporator outlet sensor of the Outlander PHEV shows the logic: the A/C amplifier sets its open-circuit code after 4 seconds of high input while READY is on or the battery is charging, and the technician measures about 5 V at the unplugged connector and checks both lines for continuity under 2 ohms. A false cold reading may lock out heating or cooling. Low counterpart: P0EC3.

Likely causes

Open signal or ground line between sensor B and module
Connector not fully seated after A/C work
Sensor B open internally

Symptoms

  • Very low refrigerant temperature shown for sensor B
  • Heating via heat pump or cooling unavailable

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–450
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

ac refrigerant temp sensor bhvac control modulewiring harness

Related codes

P0EC3P0EC1P0EC4P0EBDP0538

References: mitsubishitechinfo.com, law.cornell.edu.