Diagnostic Test

1) CHECK TO SEE IF DTC P1794 IS CURRENT
Engine Running, Shift lever in park.

With the scan tool, read the Transmission Output and Input Speed Sensor states.

Is the Output Speed Sensor reading twice the Input Speed Sensor reading?

Yes
1. Go to 2).
No
1. Go to 6).
2) 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.

With the Transmission Simulator, set the Input/Output Speed selector switch to the "3000/1000" position. Turn the Input/Output Speed switch to "ON".

Ignition on, engine not running.

With the scan tool, monitor the Input and Output Speed Sensor state.

Does the Input speed read 3000 rpm and the Output speed read 1000 rpm, within 50 rpm?

Yes
1. Go to 6).
No
1. Go to 3).
3) (T13) SPEED SENSOR GROUND CIRCUIT OPEN

Fig 1: Checking Speed Sensor Ground Circuit For Open
Courtesy 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 of the (T13) Speed Sensor Ground circuit from the appropriate terminal of Miller tool #8815 to the Transmission Solenoid/TRS Assembly and both Input and Output Speed Sensor harness connectors.

Is the resistance above 5.0 ohms on any of the above measurements?

Yes
1. Repair the (T13) Speed Sensor Ground circuit for an open.
2. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST .
No
1. Go to 4).
4) (T13) SPEED SENSOR GROUND CIRCUIT SHORT TO GROUND

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

Measure the resistance between ground and the (T13) Speed Sensor Ground circuit.

Is the resistance below 5.0 ohms?

Yes
1. Repair the (T13) Speed Sensor Ground circuit for a short to ground.
2. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST .
No
1. Go to 5).
5) (T13) SPEED SENSOR GROUND CIRCUIT SHORT TO VOLTAGE

Fig 3: Checking Speed Sensor Ground Circuit For Short To Voltage
Courtesy of CHRYSLER LLC

Ignition on, engine not running.

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

Is the voltage above 0.5 volt?

Yes
1. Repair the (T13) Speed Sensor Ground circuit for a short to voltage.
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 the PCM per the Service Information. With the scan tool, perform QUICK LEARN.
2. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST .
6) INTERMITTENT 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 DTC 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.