P1436 A/C Evaporator Air Temperature Circuit Low

Possible causes
  • ACET circuit short to ground or SIG RTN.
  • Damaged ACET sensor.
  • Damaged PCM.
    • Tech notes
    The PCM sources a low current 5 volts on the ACET circuit (this voltage can be measured with the sensor disconnected). As the 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 below the self-test minimum, check for shorts to the SIG RTN or ground, which would pull the voltage low.
    Symptoms
    – Engine Light ON (or Service Engine Soon Warning Light)
    P1436 Description
    Indicates the ACET signal input was less than the self-test minimum. The self-test minimum is 0.13 volts.