P0531

P0531-A/C PRESSURE SENSOR CIRCUIT PERFORMANCE







- When Monitored:
With the ignition on and battery voltage between 11.0 and 16.0 volts, engine running or has run this ignition cycle. No diagnosed hardware faults present for the A/C Pressure Sensor. No diagnosed stuck high or low faults present for the A/C Pressure Sensor.

- Set Condition:
The A/C Pressure Sensor signal shows an implausible result for a calibrated period of time. Two trip fault, three good trips to reset the MIL.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. DTC IS ACTIVE
1. Turn the ignition on.
2. With the scan tool, select View DTCs and review the DTC environmental information.

Is the good trip counter greater than 0?

Yes

- 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
1. Turn the ignition off.
2. Verify that the harness connector is properly connected to the A/C Pressure Transducer.
3. Disconnect the A/C Pressure Transducer connector.
4. Inspect the wiring and terminals for any condition that would result in a poor connection.
5. Look for any chafed, pierced, pinched, or partially broken wires.
6. Look for broken, bent, pushed out or corroded terminals.

Were any problems found?

Yes

- Repair as necessary.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 3

3. A/C PRESSURE TRANSDUCER VOLTAGE




1. 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.
2. Turn the ignition on.
3. 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




1. Turn the ignition off.
2. 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.
3. Turn the ignition on.
4. 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. Body Verification Test.

No

- Go To 5

5. (K301) 5 VOLT SUPPLY CIRCUIT HIGH RESISTANCE




1. Turn the ignition off.
2. Connect the A/C Pressure Transducer harness connector.
3. 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.

4. 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. Body Verification Test.

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




1. Turn the ignition off.
2. 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.

3. 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. Body Verification Test.

7. (K300) SENSOR GROUND CIRCUIT HIGH RESISTANCE




1. Turn the ignition off.
2. 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.

3. 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. Body Verification Test.

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

Were any problems found?

Yes

- Repair as necessary.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Replace and program the Gateway Module.
- Perform the BODY VERIFICATION TEST. Body Verification Test.