P0533

SYMPTOM
P0533-A/C PRESSURE SENSOR CIRCUIT HIGH

WHEN MONITORED
Engine running and the AC Clutch Relay energized.

SET CONDITION
The A/C pressure transducer signal at the PCM goes above 4.92 volts. One trip Fault. Three good trips to turn off the MIL.

POSSIBLE CAUSES
- (C18) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
- (C18) A/C PRESSURE SIGNAL CIRCUIT OPEN
- (C18) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO (T103) 5-VOLT SUPPLY CIRCUIT
- (G180) SENSOR RETURN CIRCUIT OPEN
- A/C PRESSURE TRANSDUCER
- FCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Scan Tool Testing and Procedures

DIAGNOSTIC TEST
1. A/C PRESSURE TRANSDUCER VOLTAGE ABOVE 4.9 VOLTS





Note: Make sure the A/C refrigerant System is properly charged per Service Information.

Start the engine.
With a scan tool, read the A/C Pressure Sensor voltage.
Is the voltage above 4.9 volts?
Yes>> Go To 2
No>> Perform (NGC) POWERTRAIN VERIFICATION TEST VER-2. Powertrain Verification Test - Ver 2

2. A/C PRESSURE TRANSDUCER





Turn the ignition off.
Disconnect the A/C Pressure Transducer harness connector. Connect a jumper wire between the (C18) A/C Pressure Signal circuit and the (G180) Sensor Return circuit in the Transducer harness connector.
Ignition on, engine not running.
With the scan tool, monitor the A/C Pressure Transducer voltage.
Is the voltage below 1.0 volt with the jumper wire installed?
Yes>> Replace the A/C Pressure Transducer. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-2.
No>> Go To 3 Note: Remove the jumper wire before continuing.

3. (C18) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE





Turn the ignition off.
Disconnect the C1 FCM harness connector.
Ignition on, engine not running.
Measure the voltage on the (C18) A/C Pressure Signal circuit in the A/C Pressure Transducer harness connector.
Is the voltage above 5.2 volts?
Yes>> Repair the short to battery voltage in the (C18) A/C Pressure Signal circuit. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-2.
No>> Go To 4

4. (C18) A/C PRESSURE SIGNAL CIRCUIT OPEN





Turn the ignition off.
Measure the resistance of the (C18) A/C Pressure Signal circuit from the A/C Pressure Transducer harness connector to the C1 FCM harness connector.
Is the resistance below 5.0 ohms?
Yes>> Go To 5
No>> Repair the open in the (C18) A/C Pressure Signal circuit. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-2.

5. (C18) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO THE (T103) 5-VOLT SUPPLY CIRCUIT





Measure the resistance between the (C18) A/C Pressure Signal circuit and the (T103) 5-volt Supply circuit in the A/C Pressure Transducer harness connector.
Is the resistance below 5.0 ohms?
Yes>> Repair the short between the (T103) 5-volt Supply circuit and the (C18) A/C Pressure Signal circuit. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-2.
No>> Go To 6

6. (G180) SENSOR RETURN CIRCUIT OPEN





Disconnect the C3 FCM harness connector.
Measure the resistance of the (G180) Sensor Return circuit from the A/C Pressure Sensor harness connector to the C3 FCM harness connector.
Is the resistance below 5.0 ohms?
Yes>> Go To 7
No>> Repair the open in the (G180) Sensor Return circuit. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-2.

7. FRONT CONTROL MODULE

Note: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
Were there any problems found?
Yes>> Repair as necessary. Perform BODY VERIFICATION TEST-VER 1.
No>> Replace and program the Powertrain Control Module per Service Information. Perform BODY VERIFICATION TEST VER-1.