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Home >> Ford >> 2006 >> Focus ZX5 SE, Standard >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Controls - Powertrain DTC Charts & Descriptions (Except Diesel & Hybrid) >> DTC Diagnosis >> DTC P1437: A/C Evaporator Temperature (A/CET) Circuit High Input

DTC P1437: A/C Evaporator Temperature (A/CET) Circuit High Input

P1437 - A/C EVAPORATOR TEMPERATURE (A/CET) CIRCUIT HIGH INPUT

Description:  Indicates the A/CET signal input was greater than the self-test minimum. The self-test maximum is 4.5 volts.
Possible Causes: 
  • A/CET circuit open
  • SIG RTN circuit open to A/CET sensor
  • A/CET circuit short to voltage (VREF)
  • Damaged A/CET sensor
Diagnostic Aids  : The powertrain control module (PCM) sources a low current 5 volt reference on the A/CET circuit (this voltage can be measured with the sensor disconnected). As the A/C evaporator air temperature changes, the A/CET circuit resistance to SIG RTN (ground) changes (which changes the voltage the PCM detects). When the A/CET signal is detected above the self-test maximum, check for open circuits (A/CET or SIG RTN), which would cause the voltage to remain high. Although not as probable, also check for a short to voltage (VREF).
Application  Key On Engine Off  Key On Engine Running  Continuous Memory 
All GO to Pinpoint Test DJ .
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