XB54 - Check ACP Sensor Output

- Key "OFF".

- Disconnect A/C Pressure (ACP) sensor.

- A/C system Manifold Gauge Set installed.

Testing Schematic:

- Jumper the ACP SIG RTN circuit between the ACP sensor vehicle harness connector and the ACP sensor connector.

- Jumper the ACP VREF circuit between the ACP sensor vehicle harness connector and the ACP sensor connector.

- Jumper the ACP signal circuit at the ACP sensor vehicle harness connector to the battery negative post.

- Connect a Digital Volt/Ohm Meter (DVOM) between the ACP signal circuit at the ACP sensor connector and the ACP SIG RTN circuit jumper wire.

- A/C "OFF".

- Start engine.

- Note the A/C high pressure gauge reading and the ACP sensor voltage.

- While monitoring the ACP sensor voltage, turn the A/C "ON". Ten seconds after clutch engagement, note the voltage.

- A/C "OFF".

- Key "OFF".

- Did the ACP sensor voltage change more than 0.2 volts within 10 seconds of turning the A/C "ON"?

NOTE: By listening to the A/C clutch, verify that it does not disengage during the 10 seconds of testing. If it does disengage, retest.

Yes -- Remove jumper wires. Go to XB55. (ACP sensor is operational.) XB55 - Check ACP Circuit For Short to Ground

No -- Replace ACP sensor. Remove A/C system Manifold Gauge Set. Remove jumper wires. Reconnect all components. Clear continuous memory. Clearing Diagnostic Trouble Codes

Attempt to reset Diagnostic Trouble Code (DTC) 579 (Refer to XB52 for procedure only). XB52 - Clear and Attempt to Regenerate DTC

Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)