Diagnostic Test
- CHECK DTCS
- With the scan tool, read DTCs.
Are any TIPM TCM Power Control Circuit or TCM Power Input DTCs present?
Yes
- Refer to the DTC INDEX - 2500 HD & 3500 HD article and perform the appropriate diagnostic procedure.
No
- Go To 2
- With the scan tool, read DTCs.
- CHECK IF DTC P0765 IS PRESENT
- Ignition ON, Engine Not Running.
- With the scan tool, erase all Transmission DTCs.
- Turn the ignition OFF to the LOCK position.
- Remove the Starter Relay.CAUTION:
Removal of the Starter Relay will prevent the vehicle from being started in gear.
WARNING:The Starter Relay must be removed from the PDC. Failure to do so may result in possible serious or fatal injury.
NOTE:Failure to remove the Starter Relay can cause a Transmission - No Response condition.
- Install (special tool #8333B, Simulator, Transmission).
- Ignition ON, Engine Not Running.
- With the scan tool, actuate the UD Solenoid.
- Monitor the UD Solenoid LED on the Transmission Simulator.
Did the UD Solenoid LED on the Transmission Simulator blink on and off?
Yes
- Go To 3
No
- Go To 5
- CHECK THE TRANSMISSION SOLENOID/TRS ASSEMBLY
- CHECK THE TRANSMISSION SOLENOID/TRS ASSEMBLY
- With the Transmission Simulator connected, continue to actuate the UD solenoid for another two minutes while wiggling the related wiring harness and connectors.
- Stop the actuation and check for transmission DTCs.
Did DTC P0765 reset during the actuation test?
Yes
- Repair wiring harness or connectors as necessary.
- Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to the 66RFE TRANSMISSION VERIFICATION TEST .
No
- Replace the Transmission Solenoid/TRS Assembly in accordance with the Service Information. Note: Do NOT replace the entire Valve Body.
- Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to the 66RFE TRANSMISSION VERIFICATION TEST .
- CHECK THE (T59) UD CONTROL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT
- Turn the ignition OFF to the LOCK position.
- Disconnect the (special tool #8333B, Simulator, Transmission).
- Disconnect the PCM harness connectors.
- Measure the resistance between the (T59) UD Control circuit and all other circuits in the Transmission Solenoid/TRS Assembly harness connector.
Is the resistance below 5.0 ohms between the (T59) UD Control circuit and any other circuit(s) in the Transmission Solenoid/TRS Assembly harness connector?
Yes
- Repair the (T59) UD Control circuit for a short to another circuit(s).
- Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to the 66RFE TRANSMISSION VERIFICATION TEST .
No
- Go To 6
- CHECK THE (T59) UD CONTROL CIRCUIT FOR AN OPEN
- Connect the (special tool #8815A, Kit, NGC, 38 Position) to the PCM C4 harness connector.CAUTION:
Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the Miller tool 8815A to perform diagnosis.
- Measure the resistance of the (T59) UD Control circuit from the Transmission Solenoid/TRS Assembly harness connector to the appropriate terminal of the (special tool #8815A, Kit, NGC, 38 Position).
Is the resistance above 5.0 ohms?
Yes
- Repair the (T59) UD Control circuit for an open.
- Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to the 66RFE TRANSMISSION VERIFICATION TEST .
No
- Go To 7
- Connect the (special tool #8815A, Kit, NGC, 38 Position) to the PCM C4 harness connector.
- CHECK THE (T59) UD CONTROL CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between ground and the (T59) UD Control circuit.
Is the resistance below 5.0 ohms?
Yes
- Repair the (T59) UD Control circuit for a short to ground.
- Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to the 66RFE TRANSMISSION VERIFICATION TEST .
No
- Using the schematics as a guide, check the Powertrain Control Module (PCM) terminals for corrosion, damage or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace and program the PCM in accordance with the Service Information. With the scan tool, perform a Quick Learn.
- Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to the 66RFE TRANSMISSION VERIFICATION TEST .
- Measure the resistance between ground and the (T59) UD Control circuit.