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 P1794 IS CURRENT
1. Ignition on, engine running with the Shift lever in park.
2. 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
  - Go To 2.
  No
  - Go To 6.
PCM AND WIRING
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. With the Transmission Simulator, set the Input/Output Speed selector switch to the "3000/1000" position. Turn the Input/Output Speed switch to "ON".
5. Ignition on, engine not running.
6. 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
  - Go To 6.
  No
  - Go To 3.
(T13) SPEED SENSOR GROUND CIRCUIT OPEN

Fig 1: Checking Speed Sensor Ground Circuit For Open
Courtesy of CHRYSLER LLC
1. Turn the ignition off to the lock position.
2. Disconnect the PCM C2 harness connector.
3. Disconnect the Transmission Simulator (special tool #8333A, Simulator, Transmission).
4. Measure the resistance of the (T13) Speed Sensor Ground circuit between both Input and Output Speed Sensor harness connectors and the appropriate terminal of the PCM C2 harness connector.
  Is the resistance above 5.0 Ohms on any of the above measurements?
  
  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 4.
(T13) SPEED SENSOR GROUND CIRCUIT SHORTED TO GROUND

Fig 2: 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 5.
(T13) SPEED SENSOR GROUND CIRCUIT SHORTED TO VOLTAGE

Fig 3: Checking Input Speed Sensor Ground Circuit For Open Or Short To Voltage
Courtesy of CHRYSLER LLC
1. Ignition on, engine not running.
2. With the scan tool under TIPM, actuate the Transmission.
3. 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.
  Where there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the appropriate TRANSMISSION VERIFICATION TEST. Refer to 68RFE TRANSMISSION VERIFICATION TEST .
  No
  - Test Complete.