No Response From TCM (Transmission Control Module)

NO RESPONSE FROM TCM (TRANSMISSION CONTROL MODULE) - 8HP45

For a complete wiring diagram, refer to the Wiring Information.






1. TEST FOR INTERMITTENT CONDITION

NOTE: Check for any TSB(s) related to the condition. If a TSB applies, perform the procedure outlined in the TSB before continuing.

1. Turn the ignition on.

NOTE: Make sure the battery voltage is between 10.0 and 16.0 volts.

2. With the scan tool, read the module status.

NOTE: Check the BCM for any active CAN hardware DTCs, perform DTC before proceeding.

Does the scan tool indicate that the module is active on the bus?

Yes

- The no response condition is not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring for chafed, pierced, pinched, and partially broken wires and the wiring harness connectors for broken, bent, pushed out, and corroded terminals.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 2

2. CHECK THE (A944) FUSED B(+) CIRCUIT FOR AN OPEN OR SHORT
1. Turn the ignition off.
2. Disconnect the Transmission Control Module C1 harness connector.
3. Using a 12-volt test light connected to ground, check the (A944) Fused B(+) circuit.

Does the test light illuminate brightly?

Yes

- Go To 3

No

- Repair the open or short in the (A944) Fused B(+) circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

3. CHECK THE (Z603) GROUND CIRCUIT FOR AN OPEN
1. Using a 12-volt test light connected to 12-volts, check the (Z603) Ground circuit.

Does the test light illuminate brightly?

Yes

- Go To 4

No

- Repair the (Z603) Ground circuit for an open.
- Perform the TRANSMISSION VERIFICATION TEST. Verification Tests.

4. CHECK THE (F1) FUSED IGNITION SWITCH OUTPUT (OFF-RUN-START) CIRCUIT FOR AN OPEN OR SHORT
1. Turn the ignition on.
2. Using a 12-volt test light connected to ground, check the (F1) Fused Ignition Switch Output (Off-Run-Start) circuit.

Does the test light illuminate brightly?

Yes

- Go To 5

No

- Repair the (F1) Fused Ignition Switch Output (Off-Run-Start) circuit for an open or short.
- Perform the TRANSMISSION VERIFICATION TEST. Verification Tests.

5. CHECK THE (D64) AND (D65) CAN C BUS CIRCUITS FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the Front CAN C Star Connector C6 harness connector.
3. Measure the resistance of the (D64) CAN C Bus (+) circuit between the Front CAN C Star Connector C6 harness connector and the TCM C1 harness connector.
4. Measure the resistance of the (D65) CAN C Bus (-) circuit between the Front CAN C Star Connector C6 harness connector and the TCM C1 harness connector.

Are the resistances below 5.0 Ohms?

Yes

- Replace and program the Transmission Control Module. 8HP45 TCM Programming Procedure
- Perform the TRANSMISSION VERIFICATION TEST. Verification Tests.

No

- Repair the open in the (D64) or (D65) CAN C Bus circuit.
- Perform the TRANSMISSION VERIFICATION TEST. Verification Tests.