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Home >> Jeep >> 2007 >> Commander Base, 4.7 P, AWD >> Repair and Diagnosis >> Transmission >> Transmission Control Systems >> 545RFE Automatic Transmission - Electrical Diagnostics >> Automatic Transmission 545RFE - Electrical Diagnostics >> DTC Troubleshooting >> P0934-Line Pressure Sensor Circuit Low >> Diagnostic Test

Diagnostic Test

  1. 1) CHECK IF THE DTC IS CURRENT 

    With the scan tool, read DTCs.

    Is the status Active or is the Starts Since Set counter 2 or less for this DTC? 

    Yes 

    1. Go to  2).

    No 

    1. Go to  7).
  2. 2) CHECK PCM AND WIRING 

    Turn the ignition off to the lock position.

    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 can result in personal injury or death.
    NOTE: Failure to remove the Starter Relay can cause a Transmission - No Response condition.

    Install the Transmission Simulator, Miller tool #8333.

    Ignition on, engine not running.

    With the scan tool, under Transmission Sensors, monitor the Line Pressure.

    Using the Transmission Simulator, set the rotary switch to each of the 3 line pressure positions.

    NOTE: The readings should be within ±14 kPa (2.0 psi) or 0.1 volts on the scan tool to the pressure readings specified on Transmission Simulator.

    Does the Line Pressure on the scan tool match the line pressures on the Transmission Simulator? 

    Yes 

    1. Replace the Line Pressure Sensor per the Service Information.
    2. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST .

    No 

    1. Go to  3).
  3. 3) CHECK THE (T38) LINE PRESSURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND 
    Fig 1: Checking Line Pressure Sensor Signal Circuit For Short To Ground
    GC0005177Courtesy of CHRYSLER LLC

    Turn the ignition off to the lock position.

    Disconnect the PCM C4 harness connector and connect Miller tool #8815.

    Disconnect the Transmission Simulator, Miller tool #8333.

    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 Miller tool #8815 to perform diagnosis.

    Measure the resistance between ground and the (T38) Line Pressure Sensor Signal circuit.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Repair the (T38) Line Pressure Sensor Signal circuit for a short to ground.
    2. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST .

    No 

    1. Go to  4).
  4. 4) CHECK THE (T38) LINE PRESSURE SENSOR SIGNAL CIRCUIT FOR AN OPEN 
    Fig 2: Checking Line Pressure Sensor Signal Circuit For Open
    GC0005179Courtesy of CHRYSLER LLC

    Measure the resistance of the (T38) Line Pressure Sensor Signal circuit between the Line Pressure Sensor harness connector and the appropriate terminal of Miller tool #8815.

    Is the resistance above 5.0 ohms? 

    Yes 

    1. Repair the (T38) Line Pressure Sensor Signal circuit for an open.
    2. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST .

    No 

    1. Go to  5).
  5. 5) CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR AN OPEN 
    Fig 3: Checking Line Pressure Sensor 5-Volt Supply Circuit For Open
    GC0005156Courtesy of CHRYSLER LLC

    Disconnect the PCM C1 harness connector and connect Miller tool #8815.

    Measure the resistance of the (F856) 5-volt Supply circuit between Line Pressure sensor harness connector and the appropriate terminal of Miller tool #8815.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Repair the (F856) 5-volt Supply circuit for an open.
    2. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST .

    No 

    1. Go to  6).
  6. 6) CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO GROUND 
    Fig 4: Checking Line Pressure Sensor 5-Volt Supply Circuit For Short To Ground
    GC0005157Courtesy of CHRYSLER LLC

    Disconnect the PCM C1 harness connector and connect Miller tool #8815.

    Measure the resistance between ground and the (F856) 5-volt Supply circuit.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Repair the (F856) 5-volt Supply circuit for a short to ground.
    2. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST .

    No 

    1. 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 per the Service Information. With the scan tool, perform Quick Learn.
    2. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST .
  7. 7) CHECK WIRING AND CONNECTORS 

    The conditions necessary to set this DTC are not present at this time.

    Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.

    Wiggle the wires while checking for shorted and open circuits.

    With the scan tool, check the Event Data to help identify the conditions in which the DTC was set.

    Where there any problems found? 

    Yes 

    1. Repair as necessary.
    2. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST .

    No 

    1. Test Complete.
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