Case IH 2687 – ZTC: ZTC - CAN message PTCTL1 timeout

The transmission control unit has stopped receiving the PTCTL1 (Powertrain Control 1) CAN bus message, or the message has timed out. When this message is lost, the transmission cannot properly coordinate with the engine, often resulting in degraded transmission operation, default shifting modes, or a complete loss of drive.

• Steiger T4B
• Case IH Puma
• Case IH Maxxum
• Case IH Optum
• Case IH Steiger
• Case IH Quadtrac

1. 1

   Check for accompanying CAN bus timeout codes (e.g., EEC1, EEC2, or EEC3) which indicate a physical CAN bus wiring failure rather than a specific module error.

2. 2

   Inspect the CAN High and CAN Low wiring between the Engine ECU and the ZTC (Transmission Controller) for chafing, pinch points, or melted insulation.

3. 3

   Disconnect and inspect harnesses at both the ECU and ZTC for pushed-back pins, corrosion, or moisture intrusion.

4. 4

   Test terminating resistors by measuring resistance across CAN High and CAN Low pins at the diagnostic port with the battery disconnected (should read approximately 60 ohms; 120 ohms indicates a broken resistor/wire, 0 ohms indicates a short).

5. 5

   Verify the Engine ECU is receiving proper voltage and ground to ensure it is not dropping offline and halting PTCTL1 broadcasts.

1. 1

   Disconnect Power

   Turn off the master disconnect switch or disconnect the negative battery terminal.

2. 2

   Clean and Reseat Connectors

   Apply a high-quality electrical contact cleaner to the pins on the ZTC and Engine ECU. Apply dielectric grease to the connector seals (not directly on the pins) to prevent future moisture ingress, and firmly reseat the connectors.

3. 3

   Repair Wiring

   If a break or short was found in the CAN bus wiring during diagnostics, splice in a new section of twisted-pair CAN wire. Ensure the splices are soldered and sealed with dual-wall heat shrink tubing.

4. 4

   Software Update

   If the wiring is perfectly intact, check with a Case IH EST (Electronic Service Tool) to see if there is a software update available for the ZTC or ECU. Sometimes, CAN timeout sensitivities are patched via firmware updates.

5. 5

   Module Replacement

   If the wiring is good, terminating resistors are intact, and software is up to date, the internal CAN transceiver in either the Engine ECU or the ZTC has likely failed. The ZTC will need to be replaced and reprogrammed.

6. 6

   Clear Codes and Test

   Reconnect the battery, connect the EST diagnostic tool, clear the inactive 2687 fault code, and perform a test drive to ensure the PTCTL1 message is actively communicating.