Diagnostic Test

(T78) SOLENOID SUPPLY VOLTAGE CIRCUIT SHORT TO VOLTAGE
1. With the scan tool, check for other transmission DTCs.
  Is the DTC P1629-TCM INTERNAL - SOLENOID SUPPLY/WATCHDOG also present?
  
  Yes
  - When both P0657-SOLENOID SUPPLY VOLTAGE CIRCUIT and P1629-TCM INTERNAL - SOLENOID SUPPLY/WATCHDOG DTCs set at the same time indicates that the (T78) Solenoid Supply Voltage circuit is shorted to voltage. Repair the Solenoid Supply Voltage circuit for a short to voltage. If no short to voltage is present, using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found replace the TCM in accordance with the Service Information. Refer to MODULE, TRANSMISSION CONTROL (TCM), REMOVAL .
  - Perform NAG1 TRANSMISSION VERIFICATION TEST. Refer to NAG1 TRANSMISSION VERIFICATION TEST .
  No
  - Go To 2
(T78) SOLENOID SUPPLY VOLTAGE CIRCUIT OPEN

Courtesy of CHRYSLER GROUP, LLC
1. Turn the ignition off to the lock position.
2. Disconnect the TCM C1 and C2 harness connectors.
3. Disconnect the Electrohydraulic Control Unit Assembly harness connector.
4. Measure the resistance of the (T78) Solenoid Supply Voltage circuit between the TCM C2 harness connector and the Electrohydraulic Control Unit Assembly harness connector.
  Is the resistance above 5.0 ohms?
  
  Yes
  - Repair the (T78) Solenoid Supply Voltage circuit for an open.
  - Perform NAG1 TRANSMISSION VERIFICATION TEST. Refer to NAG1 TRANSMISSION VERIFICATION TEST .
  No
  - Go To 3
(T78) SOLENOID SUPPLY VOLTAGE CIRCUIT SHORT TO GROUND

Courtesy of CHRYSLER GROUP, LLC
1. Measure the resistance between ground and the (T78) Solenoid Supply Voltage circuit.
  Is the resistance below 5.0 ohms?
  
  Yes
  - Repair the (T78) Solenoid Supply Voltage circuit for a short to ground.
  - Perform NAG1 TRANSMISSION VERIFICATION TEST. Refer to NAG1 TRANSMISSION VERIFICATION TEST .
  No
  - Go To 4
(T78) SOLENOID SUPPLY VOLTAGE CIRCUIT SHORT TO ANOTHER CIRCUIT

Courtesy of CHRYSLER GROUP, LLC
1. Measure the resistance between the (T78) Solenoid Supply Voltage circuit and all other circuits in the Electrohydraulic Control Unit Assembly harness connector.
  Is the resistance below 5.0 ohms between the (T78) Solenoid Supply Voltage circuit and any other circuit(s) in the Electrohydraulic Control Unit Assembly harness connector?
  
  Yes
  - Repair the (T78) Solenoid Supply Voltage circuit for a short to another circuit(s).
  - Perform NAG1 TRANSMISSION VERIFICATION TEST. Refer to NAG1 TRANSMISSION VERIFICATION TEST .
  No
  - Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the TCM in accordance with the Service Information. Refer to MODULE, TRANSMISSION CONTROL (TCM), REMOVAL .
  - Perform NAG1 TRANSMISSION VERIFICATION TEST. Refer to NAG1 TRANSMISSION VERIFICATION TEST .