Diagnostic Test

WARNING: This page is about a different car, the 2011 RAM Pickup. However, it is still accessible from the selected car via links, so may be relevant.

CHECK TO SEE IF DTC P0721 IS CURRENT
1. Turn the ignition off to the lock position.
  CAUTION:
  Properly support the vehicle and raise all drive wheels off the ground.
2. Release the parking brake.
3. Start the engine in park.
4. Place the transmission gear selector in drive, release foot from brake.
  WARNING:
  Be sure to keep hands and feet clear of rotating wheels.
5. With the scan tool, monitor the Output Speed Sensor RPM.
  Is the Output Speed Sensor RPM below 100 RPM?
  
  Yes
  - Go To 2.
  No
  - Go To 9.
OUTPUT SPEED SENSOR
1. Turn the ignition off to the lock position.
2. Remove the Ignition Switch Feed fuse from the TIPM.
  CAUTION:
  Removal of the Ignition Switch Feed fuse from the TIPM will prevent the vehicle from being started in gear.
  
  WARNING:
  The Ignition Switch Feed fuse must be removed from the TIPM. Failure to do so can result in possible serious or fatal injury.
3. Install the Transmission Simulator (special tool #8333A, Simulator, Transmission).
4. Ignition on, engine not running.
5. With the Transmission Simulator, set the selector switch to 3000/1000 and the Input/Output switch to ON.
6. With the scan tool, monitor the Input and Output Speed Sensor RPM
  Does the Input Speed read 3000 RPM and the Output Speed read 1000 RPM, ± 50 RPM?
  
  Yes
  - Replace the Output Speed Sensor in accordance with the Service Information.
  - Perform the appropriate TRANSMISSION VERIFICATION TEST. Refer to 68RFE TRANSMISSION VERIFICATION TEST .
  No
  - Go To 3.
CHECK THE (T14) OUTPUT SPEED SENSOR SIGNAL CIRCUIT FOR AN OPEN

Fig 1: Checking Output Speed Sensor Signal Circuit For Open
Courtesy of CHRYSLER LLC
1. Turn the ignition off to the lock position.
2. Disconnect the Transmission Simulator (special tool #8333A, Simulator, Transmission).
3. Disconnect the PCM C2 harness connector.
4. Measure the resistance of the (T14) Output Speed Sensor Signal circuit from the Output Speed Sensor harness connector to the appropriate terminal of the PCM C2 harness connector.
  Is the resistance above 5.0 Ohms?
  
  Yes
  - Repair the (T14) Output Speed Sensor Signal circuit for an open.
  - Perform the appropriate TRANSMISSION VERIFICATION TEST. Refer to 68RFE TRANSMISSION VERIFICATION TEST .
  No
  - Go To 4.
CHECK THE (T13) SPEED SENSOR GROUND CIRCUIT FOR AN OPEN

Fig 2: Checking Output Speed Sensor Ground Circuit For Open
Courtesy of CHRYSLER LLC
1. Measure the resistance of the (T13) Speed Sensor Ground circuit from the Output Speed Sensor harness connector to the appropriate terminal in the PCM C2 harness connector.
  Is the resistance above 5.0 Ohms?
  
  Yes
  - Repair the (T13) Speed Sensor Ground circuit for an open.
  - Perform the appropriate TRANSMISSION VERIFICATION TEST. Refer to 68RFE TRANSMISSION VERIFICATION TEST .
  No
  - Go To 5.
CHECK THE (T14) OUTPUT SPEED SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND

Fig 3: Checking Output Speed Sensor Signal Circuit For Short To Ground
Courtesy of CHRYSLER LLC
1. Measure the resistance between ground and the (T14) Output Speed Sensor Signal circuit.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Repair the (T14) Output Speed Sensor Signal circuit for a short to ground.
  - Perform the appropriate TRANSMISSION VERIFICATION TEST. Refer to 68RFE TRANSMISSION VERIFICATION TEST .
  No
  - Go To 6.
CHECK THE (T13) SPEED SENSOR GROUND CIRCUIT FOR A SHORT TO GROUND

Fig 4: Checking Speed Sensor Ground Circuit For Short To Ground
Courtesy of CHRYSLER LLC
1. Measure the resistance between ground and the (T13) Speed Sensor Ground circuit.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Repair the (T13) Speed Sensor Ground circuit for a short to ground.
  - Perform the appropriate TRANSMISSION VERIFICATION TEST. Refer to 68RFE TRANSMISSION VERIFICATION TEST .
  No
  - Go To 7.
CHECK THE (T14) OUTPUT SPEED SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE

Fig 5: Checking Output Speed Sensor Signal Circuit For Short To Voltage
Courtesy of CHRYSLER LLC
1. Ignition on, engine not running.
2. With the scan tool in TIPM, actuate the TCM output.
3. Measure the voltage of the (T14) Output Speed Sensor Signal circuit.
  Is the voltage above 0.5 of a volt?
  
  Yes
  - Repair the (T14) Output Speed Sensor Signal circuit for a short to voltage.
  - Perform the appropriate TRANSMISSION VERIFICATION TEST. Refer to 68RFE TRANSMISSION VERIFICATION TEST .
  No
  - Go To 8.
CHECK THE (T13) SPEED SENSOR GROUND CIRCUIT FOR A SHORT TO VOLTAGE

Fig 6: Checking Output Speed Sensor Ground Circuit For Short To Voltage
Courtesy of CHRYSLER LLC
1. With the scan tool in TIPM, actuate the TCM output.
2. Measure the voltage of the (T13) Speed Sensor Ground circuit.
  Is the voltage above 0.5 of a volt?
  
  Yes
  - Repair the (T13) Speed Sensor Ground circuit for a short to voltage.
  - Perform the appropriate TRANSMISSION VERIFICATION TEST. Refer to 68RFE TRANSMISSION VERIFICATION TEST .
  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 appropriate TRANSMISSION VERIFICATION TEST. Refer to 68RFE TRANSMISSION VERIFICATION TEST .
CHECK THE 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
  - Repair as necessary.
  - Perform the appropriate TRANSMISSION VERIFICATION TEST. Refer to 68RFE TRANSMISSION VERIFICATION TEST .
  No
  - Test Complete.