Case IH 2723 – ZTC (Zone Tractor Controller): PTCTL2 Message / SDC Signal CAN Bus Communication Timeout

The control module is failing to receive the CAN message that confirms whether the operator is physically sitting in the seat (Sitting Driver Condition). When this signal is missing or the CAN message times out, the machine will typically disable automatic drive-off, powershifting, or PTO functions.

• Steiger T4B
• Steiger
• Magnum
• Puma
• Optum
• Maxxum
• Farmall
• Case IH / Nitro series sprayers

1. 1

   Test the Operator Presence Switch for continuity using a multimeter to ensure the state changes when weight is applied to the seat.

2. 2

   Inspect the seat harness directly under the seat for chafing, pinching, or breaking caused by constant seat suspension movement.

3. 3

   Check the diagnostic menu for broader CAN faults (e.g., PTCTL1, EEC1, ECMDAT) to determine if multiple CAN messages are missing, indicating a network or controller issue rather than the seat switch.

4. 4

   Verify CAN High and CAN Low wiring integrity between the seat harness, the main cab harness, and the ZTC for shorts to ground, shorts to battery, or open circuits.

1. 1

   Access the Switch

   Tilt the seat forward or remove the bottom seat cushion to access the operator presence switch.

2. 2

   Disconnect and Inspect

   Unplug the switch connector. Inspect the pins for corrosion, moisture, or spread terminals.

3. 3

   Replace the Switch

   If the switch failed the continuity test in the diagnostic phase, remove the old switch and install the replacement.

4. 4

   Repair Wiring

   If the switch is functional, trace the wiring down the seat suspension mechanism. Cut out and solder/heat-shrink any broken wires, ensuring you leave enough slack for the seat's full range of suspension travel.

5. 5

   Clear and Verify

   Turn the key ON, clear the inactive fault codes from the ZTC, and sit in the seat. Verify that the SDC signal is now recognized and the transmission/PTO interlocks disengage.