Case IH 3096 (DTC 951B) - ECU – Engine Control Unit (ECU A-095): CAN A Bus off failure

The Engine Control Unit (ECU) detects a timeout error, an absence of communication, or a complete drop-off on the CAN A Bus network.

• MAXXUM T4E
• Case IH 240 Series Axial-Flow Combines (7240, 8240, 9240)
• Case IH Puma Series Tractors
• Case IH Magnum Series Tractors (including MX210, MX230, MX255, MX285, and newer 180-380 models)
• Case IH Steiger and Quadtrac Series Tractors

1. 1

   Verify if an external power supply was recently connected, which can temporarily disrupt the CAN network

2. 2

   Check the machine's charging system for voltage irregularities

3. 3

   Inspect the CAN line connections to other CAN devices on the network

4. 4

   Check for a faulty Central Control Unit (CCU) or Universal Control Module (UCM) that might be pulling the CAN A bus down

5. 5

   Inspect the wiring harness and connectors for damaged, bent, or dislocated pins, corroded terminals, or broken wires

6. 6

   Check the ECU A-095 to ensure it has the appropriate software version installed

1. 1

   Visual and Physical Harness Inspection

   Start by visually inspecting the CAN A Bus wiring harnesses and connectors leading to ECU A-095. Flex the involved harnesses while the machine is keyed on or operating to reveal intermittent breaks or shorts in the wiring.

2. 2

   Repair Wiring

   If you find damaged wiring, corroded terminals, or bent pins, repair the connections to restore CAN communication.

3. 3

   Test External Components

   Test the charging system and relevant solenoids for shorts that could be interfering with the ECU's power stage.

4. 4

   Software Flash

   If the wiring is intact and the fault is not resolved, the issue may be a software glitch. Connect the diagnostic tool, verify the software on ECU A-095, and re-flash/reinstall the software if necessary.

5. 5

   ECU Replacement

   If the fault persists after wiring repairs and software flashing, the failure mode is likely an internal hardware failure of the ECU A-095 power stage. The Engine Control Unit must be replaced.