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Home >> Jeep >> 2009 >> Commander Overland, RWD >> Repair and Diagnosis (Single Page) >> Transmission >> Automatic Trans >> (Powertrain Control Module (Pcm) - Electrical Diagnostics - 545RFE Automatic Transmission) >> DTC Troubleshooting >> P0934-Line Pressure Sensor Circuit Low >> Diagnostic Test
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Diagnostic Test

  1. CHECK IF THE DTC IS CURRENT 
    1. With the scan tool, read DTCs.

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

      Yes 

      • Go to step  2

      No 

      • Go to step  7
  2. CHECK 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 scan tool, under Transmission Sensors, monitor the Line Pressure.
    6. 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 

      No 

      • Go to step  3
  3. CHECK THE (T38) LINE PRESSURE SIGNAL CIRCUIT FOR A SHORT TO GROUND 
    Fig 1: Checking Line Pressure Sensor Signal Circuit For Short To Ground
    GC0106948Courtesy of CHRYSLER LLC
    1. Turn the ignition off to the lock position.
    2. Disconnect the PCM C4 harness connector and connect the PCM Pinout Box 8815.
    3. Disconnect the Transmission Simulator 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 the PCM Pinout Box 8815 to perform diagnosis.
    4. Measure the resistance between ground and the (T38) Line Pressure Signal circuit.

      Is the resistance below 5.0 Ohms?

      Yes 

      No 

      • Go to step  4
  4. CHECK THE (T38) LINE PRESSURE SIGNAL CIRCUIT FOR AN OPEN 
    Fig 2: Checking Line Pressure Signal Circuit For An Open
    GC0106950Courtesy of CHRYSLER LLC
    1. Measure the resistance of the (T38) Line Pressure Signal circuit between the Line Pressure Sensor harness connector and the appropriate terminal of the PCM Pinout Box 8815.

      Is the resistance above 5.0 Ohms?

      Yes 

      No 

      • Go to step  5
  5. CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR AN OPEN 
    Fig 3: Checking 5-Volt Supply Circuit For An Open
    GC0106924Courtesy of CHRYSLER LLC
    1. Disconnect the PCM C1 harness connector and connect the PCM Pinout Box 8815.
    2. Measure the resistance of the (F856) 5-volt Supply circuit between Line Pressure Sensor harness connector and the appropriate terminal of the PCM Pinout Box 8815.

      Is the resistance below 5.0 Ohms?

      Yes 

      No 

      • Go to step  6
  6. CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO GROUND 
    Fig 4: Checking 5-Volt Supply Circuit For A Short To Ground
    GC0106925Courtesy of CHRYSLER LLC
    1. Disconnect the PCM C1 harness connector and connect the PCM Pinout Box 8815.
    2. Measure the resistance between ground and the (F856) 5-volt Supply circuit.

      Is the resistance below 5.0 Ohms?

      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 .
  7. 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.

      Where there any problems found?

      Yes 

      No 

      • Test Complete.