Case IH 3351 – Engine Control Unit (ECU) / Vehicle Control Module (VCM): Engine compression brake low side driver circuit open failure.

The control module has detected an open circuit on the low side driver circuit that controls the engine compression brake actuator/solenoid. This means the electrical path to the compression brake is broken, disconnected, or the solenoid coil itself has failed open, preventing the engine compression brake from engaging.

• Steiger T4B
• 240 Series Axial-Flow Combines
• Magnum (250, 280, 385)
• Steiger (580, 620)
• Austoft 9900 Sugarcane Harvesters
• N-Series Loader Backhoes

1. 1

   Inspect the wiring harness routing from the Engine ECU to the engine compression brake solenoid for chafed wires, broken lines, or heat damage.

2. 2

   Disconnect the harness at the compression brake actuator and check for loose, corroded, or pushed-out pins.

3. 3

   Measure the continuity of the low side driver wire from the actuator connector back to the corresponding pin on the Engine ECU to check for a broken wire.

4. 4

   Measure the resistance across the pins of the engine compression brake solenoid itself to check if the internal coil has failed open (O.L or infinite resistance).

1. 1

   Power Down

   Turn off the machine, remove the key, and disconnect the battery to ensure safety while working on the engine electrical system.

2. 2

   Access the Actuator

   Locate the engine compression brake solenoid. (Note: Depending on the specific FPT engine model, this may be mounted externally or require removing the valve cover to access the overhead brake assembly).

3. 3

   Repair Wiring

   If the diagnostic continuity test revealed a broken wire, repair the harness using an approved OEM wiring pigtail or splice kit. Heat-shrink all connections to prevent moisture intrusion.

4. 4

   Replace Solenoid

   If the solenoid coil tested open, remove the mounting hardware securing the faulty compression brake actuator and install a new unit. Torque the mounting bolts to the engine manufacturer's specifications.

5. 5

   Reassembly

   Reconnect the electrical connector to the solenoid, ensuring the locking tab clicks into place. If the valve cover was removed, install a new valve cover gasket and reinstall the cover.

6. 6

   Clear and Test

   Reconnect the battery. Connect a diagnostic tool (such as the Case IH EST) to clear the inactive 3351 / 54F3 fault code. Start the engine and test the engine compression brake operation during a test drive to verify the repair.