P1437 Audi A/C Evaporator Air Temperature Circuit High

P1437 Audi A/C Evaporator Air Temperature Circuit High

Possible causes
  • ACET circuit open.
  • SIG RTN circuit open to the ACET sensor.
  • ACET circuit short to power (VREF).
  • Damaged ACET sensor.
  • Damaged PCM.
    • Tech description
    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 above the self-test maximum, check for open cirucits (ACET or SIG RTN), which would cause the voltage to remain high. Although not as probable, also check for a short to power (VREF).
    Symptoms
    – Engine Light ON (or Service Engine Soon Warning Light)
    P1437 Audi Description

    Indicates the ACET signal input was greater than the self-test maximum. The self-test maximum is 4.5 volts.

    Audi Vehicle:Audi A1,Audi A3,Audi A1,Audi A3,Audi A1,Audi A3,Audi A4,Audi A5,Audi Q3,Audi A5,Audi Q5,Audi A3,Audi A4,Audi A5,Audi TT,Audi Q3,Audi Q5,Audi S3,Audi TTS,Audi RS 3,Audi TT RS,Audi A7,Audi Q7,Audi A8,Audi A6,Audi S4,Audi S5,Audi Q5,Audi S6,Audi S8,Audi S5,Audi A8,Audi R8 V8,Audi RS 5,Audi S6,Audi R8 V10,Audi R8 GT,Audi A8L