Diagnostic Test
WARNING: This page is about a different car, the 2005 Jeep Grand Cherokee. 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
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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
- Repair the (T78) Solenoid Supply Voltage circuit for short to another circuit.
- Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1 .
No
- Go To step 2).
- 2) TRANSMISSION CONTROL MODULE
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Repair
- 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 ELECTRONIC CONTROL MODULES - SERVICE INFORMATION for the appropriate service procedures.
- Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1 .