P1437 FORD – A/C Evaporator Air Temperature Circuit High

P1437 FORD Possible Symptoms

Engine Light ON (or Service Engine Soon Warning Light)

P1437 FORD Possible Causes

Faulty A/C Evaporator Air Temperature (ACET) Sensor,Evaporator Temperature Sensor harness is open or shorted,Evaporator Temperature Sensor circuit poor electrical connection,Faulty Powertrain Control Module (PCM)

P1437 FORD Description

The Powertrain Control Module (PCM) detects the evaporator control circuit had a high voltage condition. The PCM sources a low current 5 volts on the A/C Evaporator Air Temperature (ACET) circuit (this voltage can be measured with the sensor disconnected). As A/C evaporator air temperature changes, the ACET circuit resistance to SIG RTN (ground) changes (which changes the voltage the PCM detects). When the ACET signal is detected above the Self-Test maximum, check for open circuits (ACET or SIG RTN), which would cause the voltage to remain high. Although not as probable, also check for a short to power (VREF).