Diagnostic Test

WARNING: This page is about a different car, the 2006 Dodge Magnum, 2006 Dodge Charger, and 2006 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.

1) CHECK THE (T78) SOLENOID SUPPLY VOLTAGE CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT

Fig 1: Checking Solenoid Supply Voltage Circuit For Short To Another Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off to the lock position.

Disconnect the TCM C1 and C2 harness connectors.

Disconnect the Transmission Electrohydraulic Control Unit Assembly harness connector.

Measure the resistance between the (T78) Solenoid Supply Voltage circuit and every other circuit in the Transmission 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 Transmission Electrohydraulic Control Unit Assembly harness connector?

Yes
1. Repair the (T78) Solenoid Supply Voltage circuit for a short to another circuit(s).
2. Perform NAG1 TRANSMISSION VERIFICATION TEST .
No
1. 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 per the Service Information. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/TRANSMISSION CONTROL MODULE - DESCRIPTION)
2. Perform NAG1 TRANSMISSION VERIFICATION TEST .