Diagnostic Test

1) CHECK TO SEE IF DTC P0721 IS CURRENT
Start the engine in park.

Raise the drive wheels off of the ground.

WARNING: Properly support the vehicle.

Firmly apply the brakes and place the transmission selector in drive.

WARNING: Be sure to keep hands and feet clear of rotating wheels.

Release the brakes and allow the drive wheels to spin freely.

NOTE: The drive wheels must be turning at this point.

With the scan tool, read the Output RPM

Is the Output RPM below 100?

Yes
1. Go To 2).
No
1. Go To 9).
2) PCM AND WIRING
Turn the ignition off to the lock position.

Remove the Starter Relay.

CAUTION: Removal of the Starter Relay is to prevent a Transmission, NO RESPONSE, condition and disable the starter.

Install the Transmission Simulator, Miller tool #8333 and the Electronic Transmission Adapter kit 8333-1A.

Ignition on, engine not running.

With the Transmission Simulator, set the "Input/Output Speed" switch to "ON" and the rotary switch to the "3000/1250" position.

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
1. Go To 3).
No
1. Go To 4).
3) OUTPUT SPEED SENSOR
If there are no possible causes remaining, view repair.

Repair
1. Replace the Output Speed Sensor per the Service Information.
2. Perform 42RLE TRANSMISSION VERIFICATION TEST .
4) (T14) OUTPUT SPEED SENSOR SIGNAL CIRCUIT OPEN

Fig 1: Checking Output Speed Sensor Signal Circuit
Courtesy of CHRYSLER LLC

Turn the ignition off to the lock position.

Disconnect the PCM C4 harness connector.

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 Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (T14) Output Speed Sensor Signal circuit from appropriate terminal of special tool #8815 to the Output Speed Sensor harness connector.

Is the resistance above 5.0 ohms?

Yes
1. Repair the (T14) Output Speed Sensor Signal circuit for an open.
2. Perform 42RLE TRANSMISSION VERIFICATION TEST .
No
1. Go To 5).
5) (T13) SENSOR GROUND CIRCUIT OPEN

Fig 2: Checking Speed Sensor Ground Circuit
Courtesy of CHRYSLER LLC

Turn the ignition off to the lock position.

Disconnect the PCM C4 harness connector.

Disconnect the Output Speed Sensor harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance of the Sensor Ground circuit from the appropriate terminal of special tool #8815 to the Output Speed Sensor harness connector.

Is the resistance above 5.0 ohms?

Yes
1. Repair the (T13) Sensor Ground circuit for an open.
2. Perform 42RLE TRANSMISSION VERIFICATION TEST .
No
1. Go To 6).
6) (T14) OUTPUT SPEED SENSOR SIGNAL CIRCUIT SHORT TO GROUND

Fig 3: Checking Output Speed Sensor Signal Circuit
Courtesy of CHRYSLER LLC

Turn the ignition off to the lock position.

Disconnect the PCM C4 harness connector.

Disconnect the Output Speed Sensor harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance between ground and the (T14) Output Speed Sensor Signal circuit.

Is the resistance below 5.0 ohms?

Yes
1. Repair the (T14) Output Speed Sensor Signal circuit for a short to ground.
2. Perform 42RLE TRANSMISSION VERIFICATION TEST .
No
1. Go To 7).
7) (T14) OUTPUT SPEED SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE

Fig 4: Checking Output Speed Sensor Signal Circuit
Courtesy of CHRYSLER LLC

Turn the ignition off to the lock position.

Disconnect the PCM C4 harness connector.

Disconnect the Output Speed Sensor harness connector.

Remove the Transmission Control Relay.

NOTE: Check connectors - Clean/repair as necessary.

Connect a jumper wire between the (Internal) Fused B+ circuit and (T16) Transmission Control Relay Output circuit in the Transmission Control Relay connector.

Ignition on, engine not running.

Measure the voltage of the (T14) Output Speed Sensor Signal circuit.

Is the voltage above 0.5 volt?

Yes
1. Repair the (T14) Output Speed Sensor Signal circuit for a short to voltage.
2. Perform 42RLE TRANSMISSION VERIFICATION TEST .
No
1. Go To 8).
8) (T13) SENSOR GROUND CIRCUIT SHORT TO VOLTAGE

Fig 5: Checking Sensor Ground Circuit
Courtesy of CHRYSLER LLC

Turn the ignition off to the lock position.

Disconnect the PCM C4 harness connector.

Remove the Transmission Control Relay.

NOTE: Check connectors - Clean/repair as necessary.

Connect a jumper wire between the (Internal) Fused B+ and (T16) Transmission Control Relay Output circuits in the Transmission Control Relay connector.

Ignition on, engine not running.

Measure the voltage of the (T13) Sensor Ground circuit.

Is the voltage above 0.5 volts?

Yes
1. Repair the (T13) Sensor Ground circuit for a short to voltage.
2. Perform 42RLE 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 the PCM per the Service Information. With the scan tool PERFORM QUICK LEARN, then program Pinion Factor in the Front Control Module. Refer to REMOVAL .
2. Perform 42RLE TRANSMISSION VERIFICATION TEST .
9) INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set the DTC are not present at this time.

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

Wiggle the wiring and connectors while checking for shorted and open circuits.

With the scan tool , check the EATX DTC EVENT DATA to help identify the conditions in which the DTC was set.

Were there any problems found?

Yes
1. Repair as necessary.
2. Perform 42RLE TRANSMISSION VERIFICATION TEST .
No
1. Test Complete.