Case IH 15338 – PVED-CLS Controller: PVED-CLS internal CAN Tx Buffer Overflow

The internal Controller Area Network (CAN) transmit (Tx) buffer of the PVED-CLS controller has filled up and overflowed. This happens when the controller attempts to send messages onto the tractor's CAN bus network but is unable to do so fast enough. This condition is typically caused by an excessive number of high-priority messages congesting the bus (bus overload), a loss of CAN communication, faulty wiring, or missing CAN terminating resistors.

• VESTRUM CVX
• Steiger
• Magnum
• Puma
• Optum
• Maxxum

1. 1

   CAN Bus Network Test: Check the CAN bus wiring harness for shorts to ground, shorts to power, or open circuits.

2. 2

   Terminating Resistors: Verify the presence and health of the CAN bus terminating resistors. With the tractor battery disconnected, measure the resistance across CAN High and CAN Low; it should read approximately 60 ohms.

3. 3

   Connector Inspection: Inspect the 12-pin Deutsch connector (DT04-12PA-B016) at the PVED-CLS module for loose contacts, corrosion, or moisture ingress.

4. 4

   Power Supply Check: Check for voltage drops or loose battery buffer connections to the steering module, which can cause the ECU to reset or drop offline.

5. 5

   Network Congestion: Check if other modules on the CAN bus are throwing communication errors or 'babbling' (sending an excessive number of erratic messages), which can cause the PVED-CLS buffer to overflow.

1. 1

   System Reset

   Power cycle the tractor. Disconnect and reconnect the main CAN/ISOBUS plug to the PVED-CLS to reset the module and clear the receive/transmit buffers.

2. 2

   Wiring Repair

   If the diagnostic checks reveal damaged CAN wiring (CAN High / CAN Low) between the steering controller and the main tractor harness, repair the wiring and apply dielectric grease to the connectors.

3. 3

   Address Reassignment

   If the tractor's modules were recently serviced, ensure the modules are wired in the correct order and reassign the CAN addresses using the Case IH Electronic Service Tool (EST).

4. 4

   Module Replacement

   If the wiring, terminating resistors, and CAN network are perfectly healthy but the PVED-CLS continues to log the Tx Buffer Overflow fault and fails to communicate, the internal CAN transceiver of the PVED-CLS has likely suffered an internal hardware failure. Replace the PVED-CLS steering controller.

5. 5

   Calibration

   After installation, the new module must be flashed with the correct parameter set and calibrated to the specific tractor's steering geometry using the Case IH EST.