A/C Pressure Sensor Volts Too Low

Name of Code:
A/C Pressure Sensor Volts Too Low

When Monitored:
With the ignition on, the engine running, and the A/C relay energized.

Set Condition:
The A/C pressure sensor signal voltage at PCM cavity 42 goes below 0.5 volt, or the voltage is below 0.098 volt.

Theory of Operation:
The A/C pressure sensor informs the PCM if the A/C system pressure is too low or too high. This information allows the PCM to determine if it can engage the compressor clutch. If the A/C system pressure is too low, the PCM will not engage the compressor clutch. If the system pressure is too high, the PCM will disengage the compressor clutch and turn on the cooling fans to prevent the compressor head pressure from becoming too high. The sensor provides a signal to PCM cavity 42. The sensor receives s 5-volt supply from PCM cavity 81. The sensor ground is provided by PCM cavity 43.

Possible Causes:
- Sensor signal shorted to ground
- Sensor internally shorted
- PCM failure