Caprice V8-265 4.3L VIN W MFI (1995)
A/C Signal: Testing and Inspection
The Powertrain Control Module (PCM) will energize the A/C clutch whenever the engine is running less than 3800 RPM and A/C has been requested
unless any of the following conditions are met:
^
Wide Open Throttle (WOT).
^
A/C head pressure greater than 429 psi or less than 0 psi (as determined by the A/C refrigerant pressure sensor),
^
Low ignition voltage.
^
Engine speed greater than 5250 RPM for 30 seconds.
^
Engine Coolant Temperature (ECT) greater than 124°C (255°F).
Chart C-10 should be used for diagnosing the electrical portion of the A/C circuit. Refer to Heating and Air Conditioning for diagnosing the refrigerant
portion of the system.
The Tech 1 will be used in diagnosing the system, as it has the ability to display the A/C request input to the PCM, A/C compressor status, A/C system
pressure, as well as displaying when the PCM has commanded the A/C clutch "ON."
