Beretta V6-3100 3.1L VIN M SFI (1995)
A/C Signal: Description and Operation
PURPOSE
The Air Conditioning (A/C) refrigerant pressure sensor provides a signal to the Powertrain Control Module (PCM) which indicates varying high
side refrigerant pressure between approximately 0 psi and 450 psi.
OPERATION
The PCM uses this input to determine A/C compressor load on the engine to help control idle speed with the Idle Air Control (IAC) valve.
The A/C refrigerant pressure sensor electrical circuit consists of a 5.0 volt reference line, a ground line, and a signal line to the PCM. The signal is
a voltage that varies from approximately 0.1 volt at 0 psi, to 4.9 volts at 450 psi or more. A problem in the A/C refrigerant pressure circuits or
sensor should set a Diagnostic Trouble Code (DTC) 66 or 70 and will make the A/C compressor clutch inoperative. A faulty ground circuit at the
sensor will result in a fixed high pressure value.
Refer to Code 66 A/C Pressure Sensor (Low) Circuit or Code 70 A/C Pressure Sensor (High) Circuit for diagnosis of the A/C refrigerant
pressure sensor. See: Testing and Inspection/Diagnostic Trouble Code Tests and Associated Procedures/Manufacturer Code Charts/DTC
66/Powertrain Controls - ECM/PCM
