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Home >> Jeep >> 2007 >> Commander Base, 4.7 P, AWD >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> DTCS P0503 To P0580 >> P0532-A/C Pressure Sensor Circuit Low >> Diagnostic Test

Diagnostic Test

  1. 1) ACTIVE DTC 
    NOTE: Diagnose any CAN - C Communication DTCs before continuing.
    NOTE: Make sure the A/C refrigerant System is properly charged per Service Information.

    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 personal injury or death.
    NOTE: Diagnose and repair any system voltage or sensor supply voltage DTCs before continuing with this test.

    With the scan tool, select View DTCs.

    Is the DTC Active at this time? 

    Yes 

    1. Go to  2).

    No 

    1. Refer to INTERMITTENT CONDITION Diagnostic Procedure.
  2. 2) (F891) 5-VOLT SUPPLY CIRCUIT 
    Fig 1: Checking A/C Pressure Sensor 5-Volt Supply Circuit
    GC0002922Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the A/C Pressure Transducer harness connector.

    Ignition on, engine not running.

    Measure the voltage on the (F891) 5-volt Supply circuit in the A/C Pressure Transducer harness connector.

    Is the voltage between 4.5 to 5.2 volts? 

    Yes 

    1. Go to  3).

    No 

    1. Go to  7).
  3. 3) A/C PRESSURE TRANSDUCER 

    With the scan tool, monitor the A/C Pressure Transducer voltage.

    NOTE: The sensor voltage should be approximately 5.0 volts (plus or minus .1 volt) with the connector disconnected.

    Does the scan tool display the voltage as described above? 

    Yes 

    1. Verify that there is good pin to terminal contact in the Transducer and Front Control Module connectors. If OK, replace the A/C Pressure Transducer.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  4).
  4. 4) (C18) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO GROUND 
    Fig 2: Checking A/C Pressure Sensor Signal Circuit For Short To Ground
    GC0002924Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the C1 FCM harness connector.

    Measure the resistance between ground and the (C18) A/C Pressure Signal circuit in the A/C Pressure Transducer harness connector.

    Is the resistance below 100 ohms? 

    Yes 

    1. Repair the short to ground in the (C18) A/C Pressure Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  5).
  5. 5) (C18) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO THE (C918) SENSOR RETURN CIRCUIT 
    Fig 3: Checking A/C Pressure Sensor Signal Circuit For Short To Sensor Ground Circuit
    GC0002925Courtesy of CHRYSLER LLC

    Disconnect the IPM FCM harness connector.

    Measure the resistance between the (C18) A/C Pressure Signal circuit and the (C918) Sensor Return circuit in the A/C Pressure Transducer harness connector.

    Is the resistance below 100 ohms? 

    Yes 

    1. Repair the short between the (C918) Sensor Return circuit and the (C18) A/C Pressure Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  6).
  6. 6) EXCESSIVE RESISTANCE IN THE (C18) A/C PRESSURE SIGNAL CIRCUIT 
    Fig 4: Checking A/C Pressure Sensor Signal Circuit
    GC0011604Courtesy of CHRYSLER LLC

    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 

    1. Go to  9).

    No 

    1. Repair the excessive resistance in the (C18) A/C Pressure Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  7. 7) (F891) 5-VOLT SUPPLY CIRCUIT OPEN 
    Fig 5: Checking A/C Pressure Sensor 5-Volt Supply Circuit
    GC0011602Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the C1 FCM harness connector.

    Measure the resistance of the (F891) 5-volt Supply circuit from the A/C Pressure Transducer harness connector to the C1 FCM harness connector.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Go to  8).

    No 

    1. Repair the open in the (F891) 5-volt Supply circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  8. 8) (F891) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND 
    Fig 6: Checking A/C Pressure Sensor 5-Volt Supply Circuit For Short To Ground
    GC0002923Courtesy of CHRYSLER LLC

    Measure the resistance between ground and the (F891) 5-volt Supply circuit in the A/C Pressure Transducer harness connector.

    Is the resistance below 100 ohms? 

    Yes 

    1. Repair the short to ground in the (F891) 5-volt Supply circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  9).
  9. 9) FRONT CONTROL MODULE (FCM) 

    Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the A/C Pressure Transducer and the Front Control Module (FCM).

    Look for any chafed, pierced, pinched, or partially broken wires.

    Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Transducer and Front Control Module connectors.

    Refer to any Technical Service Bulletins that may apply.

    Were there any problems found? 

    Yes 

    1. Repair as necessary.
    2. Perform BODY VERIFICATION TEST .

    No 

    1. Replace and program the Front Control Module per Service Information.
    2. Perform BODY VERIFICATION TEST .
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