Case IH 2705 – Transmission Control Unit (TCU / TRANS) or Vehicle Domain Controller (VDC) / User Controller (UC): CAN message PTCTL1 and DTRR signal error or timeout

The "PTCTL1" (Powertrain Control 1) message is failing because the "DTRR" (Desired Transmission Reciprocal Ratio) signal from the user controller is faulty, missing, or experiencing a timeout. This means the transmission control unit is not receiving the required reciprocal ratio data to operate the transmission properly.

• Steiger T4B

1. 1

   Check the CAN bus wiring for any broken wires or loose connectors.

2. 2

   Test the CAN wire/connector to see if it is defective, shorted to vehicle ground, or shorted to battery voltage.

3. 3

   Verify if there is electrical interference on the CAN-Bus.

4. 4

   Check the User Controller (UC) or Engine Controller (EC/MC) for internal faults.

1. 1

   Prepare machine

   Stop the engine and remove the key from the starter switch.

2. 2

   Disconnect battery

   Before working on the electrical systems, disconnect the battery terminals to prevent damage.

3. 3

   Unplug connectors

   Unplug all the connectors of the electronic control units and the alternator.

4. 4

   Inspect CAN wiring

   Inspect the CAN bus wiring harness and connectors between the User Controller and the Transmission Control Unit for breaks, corrosion, or shorts to ground/battery voltage.

5. 5

   Repair wiring

   Repair or replace any damaged sections of the CAN wiring harness or connectors.

6. 6

   Reconnect control units

   Reconnect all control unit connectors.

7. 7

   Reconnect battery

   Reconnect the battery terminals—always connect the positive terminal (+) first, and then the negative (-).

8. 8

   Replace controllers

   If the wiring and connectors are completely intact but the fault persists, the User Controller (UC) or Transmission Controller is likely defective and must be replaced.