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Home >> Jeep >> 2009 >> Commander Overland, RWD >> Repair and Diagnosis >> Transmission >> Automatic Trans >> (Powertrain Control Module (Pcm) - Electrical Diagnostics - 545RFE Automatic Transmission) >> DTC Troubleshooting >> P0876-UD Pressure Switch Rationality >> Diagnostic Test

Diagnostic Test

  1. CHECK FOR RELATED DTCS 
    1. With the scan tool, read DTCs.

      Are there any TCM Power Input, Line Pressure, and/or Loss of Prime DTCs present?

      Yes 

      No 

      • Go to step  2
  2. CHECK FOR PRESSURE SWITCH DTCS 

    Are there two or more other pressure switch rationality DTCs present in addition to P0876?

    Yes 

    • Go to step  3

    No 

    • Go to step  4
  3. CHECK IF ALL PRESSURE SWITCHES READ CLOSED 
    1. With the scan tool, read and record all Event Data.
      NOTE: Make sure to record all Event Data stored in the scan tool for future reference in this test procedure.

      Does the Event Data show all pressure switches reading CLOSED?

      Yes 

      No 

      • Go to step  4
  4. CHECK FOR OTHER DTCS 
    1. With the scan tool, read DTCs.

      Is the DTC P2704 present also?

      Yes 

      No 

      • Go to step  5
  5. CHECK THE EVENT DATA 

    In the Event Data recorded earlier, does the Event Data display information for the DTC P0876?

    Yes 

    • Go to step  6

    No 

  6. CHECK IF EVENT DATA WAS SET IN PARK, NEUTRAL OR REVERSE 

    In the Event Data recorded earlier, did the DTC P0876 set in Park, Neutral, or Reverse?

    Yes 

    • Go to step  10

    No 

    • Go to step  7
  7. CHECK FOR UD PRESSURE SWITCH STATUS 

    In the Event Data recorded earlier, did the DTC P0876 set with the UD Pressure Switch closed?

    Yes 

    • Go to step  10

    No 

    • Go to step  8
  8. CHECK LINE PRESSURE 

    In the Event Data recorded earlier, is the Line Pressure less than 40 psi, and significantly below the Desired Line Pressure?

    Yes 

    • Repair as necessary to correct low line pressure. Check fluid level and adjust as necessary. If fluid level is OK, check the Primary Oil Filter seal for a split, crack, or improperly installed. If the filter and seal are OK, check the Main Regulator Valve in the Oil Pump. Refer to the appropriate Service Information for the above procedures.
    • Perform the 545RFE TRANSMISSION VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .

    No 

    • Go to step  9
  9. CHECK THE (T29) UD PRESSURE SIGNAL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT 
    Fig 1: Checking UD Pressure Signal Circuit For A Short To Another Circuit
    GC0106937Courtesy of CHRYSLER LLC
    1. Turn the ignition off to the lock position.
    2. Disconnect all PCM harness connectors.
    3. Disconnect the Transmission Solenoid/TRS Assembly harness connector.
    4. Measure the resistance between the (T29) UD Pressure Signal circuit and all other circuits in the Transmission Solenoid/TRS Assembly harness connector.

      Is the resistance below 5.0 Ohms between the (T29) UD Pressure Signal circuit and any other circuit(s) in the Transmission Solenoid/TRS Assembly harness connector?

      Yes 

      No 

  10. CHECK THE PCM AND WIRING 
    1. Turn the ignition off to the lock position.
    2. Remove the Starter Relay.
      CAUTION: Removal of the Starter Relay will prevent the vehicle from being started in gear.
      WARNING: The Starter Relay must be removed from the PDC. Failure to do so may result in possible serious or fatal injury.
      NOTE: Failure to remove the Starter Relay can cause a Transmission - No Response condition.
    3. Install the Transmission Simulator 8333.
    4. Ignition on, engine not running.
    5. With the Transmission Simulator, turn the Pressure Switch selector switch to the UD position.
    6. With the scan tool, monitor the UD Pressure Switch state while pressing the Pressure Switch Test button on the Transmission Simulator.

      Did the state of the UD Pressure Switch change while pressing the Pressure Switch Test button?

      Yes 

      • Go to step  14

      No 

      • Go to step  11
  11. CHECK THE (T29) UD PRESSURE SIGNAL CIRCUIT FOR AN OPEN 
    Fig 2: Checking UD Pressure Signal Circuit For An Open
    GC0106938Courtesy of CHRYSLER LLC
    1. Turn the ignition off to the lock position.
    2. Disconnect the Transmission Simulator 8333.
    3. Disconnect the PCM C4 harness connector and connect the PCM Pinout Box 8815.
      CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the PCM Pinout Box 8815 to perform diagnosis.
    4. Measure the resistance of the (T29) UD Pressure Signal circuit from the Transmission Solenoid/TRS Assembly harness connector and the appropriate terminal of the PCM Pinout Box 8815.

      Is the resistance above 5.0 Ohms?

      Yes 

      No 

      • Go to step  12
  12. CHECK THE (T29) UD PRESSURE SIGNAL CIRCUIT FOR A SHORT TO GROUND 
    Fig 3: Checking UD Pressure Signal Circuit For A Short To Ground
    GC0106939Courtesy of CHRYSLER LLC
    1. Measure the resistance between ground and the (T29) UD Pressure Signal circuit.

      Is the resistance below 5.0 Ohms?

      Yes 

      No 

      • Go to step  13
  13. CHECK THE (T29) UD PRESSURE SIGNAL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT 
    Fig 4: Checking UD Pressure Signal Circuit For A Short To Another Circuit
    GC0106937Courtesy of CHRYSLER LLC
    1. Disconnect all PCM harness connectors.
      NOTE: Make sure the Transmission Solenoid/TRS Assembly harness connector is disconnected.
    2. Measure the resistance between the (T29) UD Pressure Signal circuit and all other circuits in the Transmission Solenoid/TRS Assembly harness connector.

      Is the resistance below 5.0 Ohms between the (T29) UD Pressure Signal circuit and any other circuit(s) in the Transmission Solenoid/TRS Assembly harness connector?

      Yes 

      No 

      • Using the schematics as a guide, check the Powertrain Control Module (PCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace and program the PCM in accordance with the Service Information. With the scan tool, perform Quick Learn.
      • Perform the 545RFE TRANSMISSION VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  14. WIGGLE TEST USING THE TRANSMISSION SIMULATOR 
    1. Perform the steps in the previous test while wiggling the wiring harness and connectors pertaining to the UD Pressure Switch.

      Did the state of the UD Pressure Switch change while pressing the Pressure Switch Test button?

      Yes 

      No 

      • Go to step  15
  15. CHECK THE TRANSMISSION SOLENOID/TRS ASSEMBLY 
    Fig 5: Checking UD Pressure Switch Sense Circuit
    GC0090608Courtesy of CHRYSLER LLC
    1. Disconnect the Transmission Simulator and reconnect the Transmission Solenoid/TRS Assembly harness connector.
    2. Disconnect the PCM C4 harness connector and connect the PCM Pinout Box 8815.
    3. Measure the resistance between ground and the (T29) UD Pressure Signal circuit in the appropriate terminal of the PCM Pinout Box 8815.

      Is the resistance below 5.0 Ohms?

      Yes 

      No 

      • Go to step  16
  16. CHECK IF THE DTC RESETS 
    1. Reconnect all previously disconnected connectors.
    2. With the scan tool, erase all transmission DTCs.
    3. Test drive the vehicle. Using the Event Data recorded earlier, try to duplicate the conditions in which the DTC originally set.

      Does the DTC P0876 reset?

      Yes 

      • Go to step  17

      No 

      • Go to step  18
  17. CHECK FOR A CUT NO. 2 CHECK BALL 
    1. Remove the Valve Body in accordance with the Service Information.
    2. Check the No. 2 check ball for cuts or damage.

      Is the No. 2 check ball cut or damaged?

      Yes 

      No 

  18. CHECK WIRING AND CONNECTORS 
    1. The conditions necessary to set this DTC are not present at this time.
    2. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
    3. Wiggle the wires while checking for shorted and open circuits.
    4. With the scan tool, check the Event Data to help identify the conditions in which the DTC was set.

      Were there any problems found?

      Yes 

      No 

      • Test Complete.
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