P0531

P0531-A/C PRESSURE SENSOR CIRCUIT PERFORMANCE





For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.

- Set Condition:
The PCM detects that the A/C Pressure Transducer input voltage is implausible.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Initial Inspection and Diagnostic Overview

Diagnostic Test

1. DTC IS ACTIVE
Turn the ignition on.
With the scan tool, select View DTCs and review the DTC environmental information.
Is the good trip counter greater than 0?

Yes

- The DTC is not active at this time. Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.Checking for an Intermittent DTC

No

- Go to 2

2. A/C PRESSURE TRANSDUCER WIRING AND CONNECTOR INSPECTION
Turn the ignition off.
Verify that the harness connector is properly connected to the A/C Pressure Transducer.
Disconnect the A/C Pressure Transducer connector.
Inspect the wiring and terminals for any condition that would result in a poor connection.
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Were any problems found?

Yes

- Repair as necessary.
- Perform the Body Verification Test Ver. 1. Body Verification Test

No

- Go to 3

3. A/C PRESSURE TRANSDUCER VOLTAGE




Connect a jumper wire between the (K301) 5 Volt Supply circuit and the (C18) A/C Pressure Transducer Signal circuit in the A/C Pressure Transducer harness connector.
Turn the ignition on.
With the scan tool, read the A/C Pressure Transducer input voltage.

NOTE: The sensor voltage should be approximately 5.0 volts (plus or minus.1 volt) with the jumper wire in place.

Is the voltage on the scan tool displayed as described above?

Yes

- Go to 4

No

- Go to 5

4. A/C PRESSURE TRANSDUCER




Turn the ignition off.
Connect a jumper wire between the (K300) Sensor Ground circuit and the (C18) A/C Pressure Transducer Signal circuit in the A/C Pressure Transducer harness connector.
Turn the ignition on.
With the scan tool, read the A/C Pressure Transducer input voltage.

NOTE: The sensor voltage should be approximately 0.0 volts (plus or minus.1 volt) with the jumper wire in place.

Is the voltage on the scan tool displayed as described above?

Yes

- Replace the A/C Pressure Transducer.
- Perform the Body Verification Test Ver. 1. Body Verification Test

No

- Go to 5

5. (K301) 5 VOLT SUPPLY CIRCUIT HIGH RESISTANCE




Turn the ignition off.
Connect the A/C Pressure Transducer harness connector.
Using a voltmeter, perform a voltage drop test by backprobing the (K301) 5 Volt Supply circuit at the A/C Pressure Transducer and Gateway Module harness connectors. Make sure the voltmeter leads are connected so that positive polarity is displayed on the voltmeter.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose fitting clothing. Failure to follow these instructions can result in personal or fatal injury.

Start the engine.
Is the voltage below 0.5 volts?

Yes

- Go to 6

No

- Repair the (K301) 5 Volt Supply circuit for high resistance.
- Perform the Body Verification Test Ver. 1. Body Verification Test

6. (C18) A/C PRESSURE TRANSDUCER SIGNAL CIRCUIT HIGH RESISTANCE




Turn the ignition off.
Using a voltmeter, perform a voltage drop test by backprobing the (C18) A/C Pressure Transducer Signal circuit at the A/C Pressure Transducer and Gateway Module harness connectors. Make sure the voltmeter leads are connected so that positive polarity is displayed on the voltmeter.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose fitting clothing. Failure to follow these instructions can result in personal or fatal injury.

Start the engine.
Is the voltage below 0.5 volts?

Yes

- Go to 7

No

- Repair the (C18) A/C Pressure Transducer Signal circuit for high resistance.
- Perform the Body Verification Test Ver. 1. Body Verification Test

7. (K300) SENSOR GROUND CIRCUIT HIGH RESISTANCE




Turn the ignition off.
Using a voltmeter, perform a voltage drop test by backprobing the (K300) Sensor Ground circuit at the A/C Pressure Transducer and Gateway Module harness connectors. Make sure the voltmeter leads are connected so that positive polarity is displayed on the voltmeter.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose fitting clothing. Failure to follow these instructions can result in personal or fatal injury.

Start the engine.
Is the voltage below 0.5 volts?

Yes

- Go to 8

No

- Repair the (K300) Sensor Ground circuit for high resistance.
- Perform the Body Verification Test Ver. 1. Body Verification Test

8. GATEWAY MODULE
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the A/C Pressure Transducer and the Gateway Module.
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
Look for the data to change or for a DTC to set during the wiggle test.
Search for any Technical Service Bulletins that may apply.
Were any problems found?

Yes

- Repair as necessary.
- Perform the Body Verification Test Ver. 1. Body Verification Test

No

- Replace and program the Gateway Module.
- Perform the Body Verification Test Ver. 1. Body Verification Test