P0533
P0533-A/C PRESSURE SENSOR CIRCUIT HIGH
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The A/C pressure transducer monitors the pressures in the high side of the A/C refrigerant system through its connection to a fitting on the A/C discharge line and its internal resistance changes in response to the pressures it monitors. The Totally Intergrated Power Module (TIPM) provides a five Volt reference and a sensor ground to the A/C pressure transducer, then monitors the output voltage of the transducer on a sensor signal circuit to determine refrigerant pressure that the TIPM busses to the Powertrain Control Module (PCM). The PCM is programmed to respond to this and other sensor inputs by controlling the operation of the A/C clutch and the radiator cooling fan to help optimize A/C system performance and to protect the A/C system components from damage. The PCM will request disengagement of the A/C clutch when high side pressure rises above 3219 kPa (476 psi) and re-engage the clutch when high side pressure drops below 2937 kPa (426 psi). The PCM will also disengage the A/C clutch if the high side pressure drops below 110 kPa (16 psi) and will re-engage the clutch when the high side pressure rises above 220 kPa (32 psi). When the refrigerant pressure rises above 1655 kPa (240 psi), the PCM will actuate the cooling fan.
- When Monitored:
Engine running and the A/C Clutch Relay energized.
- Set Condition:
The A/C pressure transducer signal at the PCM goes above the maximum acceptable voltage. One trip Fault. Three good trips to turn off the MIL.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
1. ACTIVE DTC
NOTE: Diagnose and repair any CAN bus, communication or implausible signal DTCs before proceeding with this test.
NOTE: Diagnose and repair any system voltage or sensor supply voltage DTCs before continuing with this test.
NOTE: Make sure the A/C refrigerant System is properly charged. . Specifications
1. Start the engine and allow it to reach normal operating temperature.
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 clothing. Failure to follow these instructions can result in possible serious or fatal injury.
2. With the scan tool, select View DTCs.
Is the DTC Active at this time?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. . Intermittent Condition Test
2. (C818) A/C PRESSURE SENSOR SUPPLY CIRCUIT SHORTED TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the A/C Pressure Transducer harness connector.
3. Disconnect the Totally Integrated Power Module (TIPM) C1 harness connector.
4. Turn the ignition on.
5. Measure the voltage of the (C818) A/C Pressure Sensor Supply circuit in the A/C Pressure Transducer harness connector.
Is there any voltage present?
Yes
- Repair the (C818) A/C Pressure Sensor Supply circuit for a short to voltage.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 3
3. (C18) A/C PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE
1. Measure the voltage of the (C18) A/C Pressure Sensor Signal circuit in the A/C Pressure Transducer harness connector.
Is there any voltage present?
Yes
- Repair the (C18) A/C Pressure Sensor Signal circuit for a short to voltage.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 4
4. (C18) A/C PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO THE (C818) A/C PRESSURE SENSOR SUPPLY CIRCUIT
1. Measure the resistance between the (C18) A/C Pressure Sensor Signal circuit and the (C818) A/C Pressure Sensor Supply circuit in the A/C Pressure Transducer harness connector.
Is the resistance below 100 Ohms?
Yes
- Repair the (C18) A/C Pressure Sensor Signal circuit for a short to the (C818) A/C Pressure Sensor Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 5
5. (C18) A/C PRESSURE SENSOR SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE
1. Turn the ignition off.
2. Measure the resistance of the (C18) A/C Pressure Sensor Signal circuit between the A/C Pressure Transducer harness connector and the Totally Integrated Power Module (TIPM) harness connector.
Is the resistance below 5.0 Ohms?
Yes
- Go To 6
No
- Repair the (C18) A/C Pressure Sensor Signal circuit for an open circuit or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
6. (C918) A/C PRESSURE SENSOR GROUND CIRCUIT OPEN OR HIGH RESISTANCE
1. Measure the resistance of the (C918) A/C Pressure Sensor Ground circuit between the A/C Pressure Transducer harness connector and the Totally Integrated Power Module (TIPM) harness connector.
Is the resistance below 5.0 Ohms?
Yes
- Go To 7
No
- Repair the (C918) A/C Pressure Sensor Ground circuit for an open circuit or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
7. A/C PRESSURE TRANSDUCER
1. Turn the ignition off.
2. Connect the Totally Integrated Power Module (TIPM) connector.
3. Connect a jumper wire between the (C918) A/C Pressure Sensor Ground circuit and the (C18) A/C Pressure Sensor Signal circuit in the A/C Pressure Transducer harness connector.
4. Turn the ignition on.
5. With the scan tool, read the A/C Pressure Transducer signal voltage.
Is the voltage below 1.0 Volt with the jumper wire in place?
Yes
- Replace the A/C Pressure Transducer.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 8
8. TOTALLY INTEGRATED POWER MODULE (TIPM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the A/C Pressure Transducer and the Totally Integrated Power Module (TIPM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Perform 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 Totally Integrated Power Module (TIPM).
- Perform the BODY VERIFICATION TEST. Body Verification Test.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.