Case IH 3338 (DTC 91CB / 92CB) - ECU – Engine Control Unit (ECU A-095): CAN communication failure between vehicle controller and ECU controller - TSC1_VE message

The Engine Control Unit (ECU) is failing to receive the expected TSC1_VE communication message over the Controller Area Network (CAN) bus from the main vehicle controller.

• MAXXUM T4E
• Case IH Puma Series Tractors
• Case IH Magnum 235 - 340 (Series 4) Tractors
• Case IH 240 Series Axial-Flow Combines

1. 1

   Check if the tractor battery power supply has been connected to an external power supply (such as a jump starter or external charger).

2. 2

   Test the machine's charging system for faults, as improper voltage can disrupt CAN communication.

3. 3

   Inspect the CAN bus twisted pair wiring harness for faults, specifically looking for damaged, bent, or displaced pins, corroded terminals, or broken wires between the vehicle controller and the ECU.

4. 4

   Check for a faulty Central Control Unit (CCU) / Universal Control Module (UCM) or a faulty solenoid that might be pulling down the CAN network.

1. 1

   Disconnect External Power

   If an external power supply is connected to the tractor, disconnect it immediately and test the system for normal operation. External power sources are a primary known cause of this specific communication failure.

2. 2

   Inspect Connectors

   Verify that all connectors between the Central Control Unit (CCU) and the ECU A-095 are completely seated and locked.

3. 3

   Flex Test the Harness

   While operating the machine and observing the monitor, flex the involved wiring harnesses to reveal any intermittent breaks or short circuits in the wiring. Repair any damaged wiring or pins found during this test.

4. 4

   Test the Charging System

   Verify the alternator and batteries are providing the correct operating voltage to the ECU and CCU.

5. 5

   Software Verification

   If the wiring is intact and the fault has not been resolved, verify that the appropriate software is present on the ECU A-095. Reinstall or flash the ECU software if necessary.

6. 6

   Module Replacement

   If all wiring, voltage, and software checks pass, the failure is likely internal to the Central Control Unit (CCU) or the Engine Control Unit (ECU A-095), requiring module replacement.