No Response From TCM

POSSIBLE CAUSES
- Traction system relay output circuit open
- Ground circuit open
- SCI transmit circuit open
- SCI transmit circuit shorted to ground
- SCI transmit circuit shorted to voltage
- Transmission control module

Diagnostic Test




1. TRACTION SYSTEM RELAY OUTPUT CIRCUIT OPEN

Turn the ignition off.
Disconnect the TCM harness connector.

NOTE: Check connector Clean/repair as necessary.

Turn the ignition on.
Measure the voltage of the Traction System Relay Output circuit at the TCM harness connector.

Q: Is the voltage above 10 volts?

YES: Go to 2
NO: Repair the Traction System Relay Output circuit for an open. Perform NAG1 TRANSMISSION VERIFICATION TEST.




2. GROUND CIRCUIT OPEN

Turn the ignition off.
Measure the resistance of the Ground circuit from the TCM harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Go to 3
NO: Repair the Ground circuit for an open. Perform NAG1 TRANSMISSION VERIFICATION TEST.




3. SCI TRANSMIT CIRCUIT OPEN

With the ignition off.
Measure the resistance of the SCI Transmit circuit from the TCM harness connector to the DLC.

Q: Is the resistance below 5.0 ohms?

YES: Go to 4
NO: Repair the SCI Transmit circuit for an open. Perform NAG1 TRANSMISSION VERIFICATION TEST.




4. SCI TRANSMIT CIRCUIT SHORTED TO GROUND

With the ignition off.
Measure the resistance between ground and the SCI Transmit circuit.

Q: Is the resistance below 100 kohms?

YES: Repair the SCI Transmit circuit for a short to ground. Perform NAG1 TRANSMISSION VERIFICATION TEST.
NO: Go to 5




5. SCI TRANSMIT CIRCUIT SHORTED TO VOLTAGE

Turn the ignition on.
Measure the voltage of the SCI Transmit circuit at the TCM.

Q: Is the voltage above 0.5 volt?

YES: Repair the SCI Transmit circuit for a short to voltage. Perform NAG1 TRANSMISSION VERIFICATION TEST.
NO: Replace the Transmission Control Module. Perform NAG1 TRANSMISSION VERIFICATION TEST.