P0538 – A/C Evaporator Temperature Circuit High Input

P0538 Possible Symptoms

Engine Light ON (or Service Engine Soon Warning Light),A/C Inoperative,A/C Blows Warm

P0538 Possible Causes

Faulty A/C Evaporator Temperature Sensor,A/C Evaporator Temperature Sensor harness is open or shorted,A/C Evaporator Temperature Sensor circuit poor electrical connection

P0538 Description

The Powertrain Control Module (PCM) sources a low current 5 volts on the A/C Evaporator Temperature (ACET) sensor circuit. As the A/C evaporator air temperature changes, the ACET circuit resistance changes (which changes the voltage the PCM detects).