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

When is the code detected?

When the A/C Evaporator Temperature (ACET) sensor signal is high the Powertrain Control Module (PCM) will triggered the P0538 code.

Symptoms

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

P0538 FORD 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).