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Home >> Dodge and Ram >> 2009 >> Durango Base, 4.7 P, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 12 (Powertrain Control Module (Pcm) - Electrical Diagnostics - 42RLE) >> DTC Troubleshooting >> P0721-Output Speed Sensor Circuit Performance >> Diagnostic Test
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Diagnostic Test

WARNING: This page is about a different variant/trim than selected.
  1. CHECK IF THE DTC IS CURRENT 
    1. Start the engine in park.
    2. Raise the drive wheels off of the ground.
      WARNING: Properly support the vehicle.
    3. Firmly apply the brakes and place the transmission selector in drive.
      WARNING: Be sure to keep hands and feet clear of rotating wheels.
    4. Release the brakes and allow the drive wheels to spin freely.
      NOTE: The drive wheels must be turning at this point.
    5. With the scan tool, read the Output RPM

      Is the Output RPM below 100?

      Yes 

      • Go to step  2

      No 

      • Go to step  8
  2. CHECK THE PCM AND WIRING USING THE TRANSMISSION SIMULATOR 
    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, Miller tool #8333A and the Electronic Transmission Adapter kit.
    4. Ignition on, engine not running.
    5. With the Transmission Simulator, set the "Input/Output Speed" switch to "ON" and the rotary switch to the "3000/1250" position.
    6. With the scan tool , read the Input and Output RPM.

      Does the Input RPM read 3000 and the Output RPM read 1250 (within 50 RPM)?

      Yes 

      No 

      • Go to step  3
  3. CHECK THE (T14) OUTPUT SPEED SIGNAL CIRCUIT FOR AN OPEN 
    Fig 1: Checking Output Speed Sensor Signal Circuit
    GC0090505Courtesy of CHRYSLER LLC
    1. Turn the ignition off to the lock position.
    2. Disconnect the PCM C4 harness connector.
    3. Disconnect the Output Speed Sensor harness connector.
      NOTE: Check connectors - Clean/repair as necessary.
      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 (T14) Output Speed Signal circuit between the Output Speed Sensor harness connector and the appropriate terminal of Miller tool #8815.

      Is the resistance above 5.0 ohms?

      Yes 

      No 

      • Go to step  4
  4. CHECK THE (T13) SPEED SENSOR GROUND CIRCUIT FOR AN OPEN 
    Fig 2: Checking Speed Sensor Ground Circuit
    GC0090506Courtesy of CHRYSLER LLC
    1. Measure the resistance of the Speed Sensor Ground circuit between the appropriate terminal of Miller tool #8815 and the Output Speed Sensor harness connector.

      Is the resistance above 5.0 ohms?

      Yes 

      No 

      • Go to step  5
  5. CHECK THE (T14) OUTPUT SPEED SIGNAL CIRCUIT FOR A SHORT TO GROUND 
    Fig 3: Checking Output Speed Sensor Signal Circuit
    GC0090507Courtesy of CHRYSLER LLC
    1. Measure the resistance between ground and the (T14) Output Speed Signal circuit.

      Is the resistance below 5.0 ohms?

      Yes 

      No 

      • Go to step  6
  6. CHECK THE (T14) OUTPUT SPEED SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE 
    Fig 4: Checking Output Speed Signal Circuit Short To Voltage
    GC0106867Courtesy of CHRYSLER LLC
    1. Remove the Transmission Control Relay.
    2. Connect a jumper wire between the (A104) Fused B(+) circuit and (T16) Transmission Control Relay Output circuit in the Transmission Control Relay connector.
    3. Ignition on, engine not running.
    4. Measure the voltage of the (T14) Output Speed Signal circuit.

      Is the voltage above 0.5 volt?

      Yes 

      No 

      • Go to step  7
  7. CHECK THE (T13) SPEED SENSOR GROUND CIRCUIT FOR A SHORT TO VOLTAGE 
    Fig 5: Checking Speed Sensor Ground Circuit Short To Voltage
    GC0106866Courtesy of CHRYSLER LLC
    NOTE: The jumper wire must still be connected.
    1. Measure the voltage of the (T13) Speed Sensor Ground circuit.

      Is the voltage above 0.5 volts?

      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. Check for Service Information Tune-ups or Service Bulletins for any possible causes that may apply. If no problems are found, replace and program the PCM in accordance with the Service Information. With the scan tool, perform Quick Learn.
      • Perform 42RLE TRANSMISSION VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure 
  8. CHECK THE WIRING AND CONNECTORS 
    1. The conditions necessary to set the 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 wiring and connectors 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.
    5. Check for Service Information Tune-ups or Service Bulletins for any possible causes that may apply.

      Were there any problems found?

      Yes 

      No 

      • Test Complete.
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