Case IH 3354 – Engine Controller (ECM / EDC): Main Relay 4 (Engine Brake Exhaust Valve) Short circuit to Ground

The electrical circuit supplying power to the exhaust brake flap actuator (or its controlling relay) has shorted to the chassis/ground. The exhaust brake is an electrically controlled throttling valve located in the exhaust plumbing at the outlet of the turbocharger that restricts exhaust flow to place a load on the engine, elevating exhaust temperatures for the SCR and DOC.

• Magnum 235-340 (Series 4)
• Steiger series
• Puma series
• Vestrum series (100, 110, 120, 130)
• Axial-Flow 7230
• Axial-Flow 8230
• Axial-Flow 9230

1. 1

   Inspect the wiring harness running from the Engine Controller (ECM) to the exhaust brake flap actuator for chafed insulation, pinched wires, or rubbing against the hot exhaust or engine block.

2. 2

   Disconnect the exhaust brake actuator and the ECM, then use a multimeter to check for continuity to ground on the High side supply #4 wire.

3. 3

   Test the pins on the exhaust brake flap actuator itself to check for an internal solenoid short to ground.

4. 4

   Locate Main Relay 4 in the power distribution box, test for internal shorts, and inspect the socket for melted plastic or corroded terminals.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery cable to prevent ECU damage.

2. 2

   Locate the Valve

   Locate the exhaust brake flap actuator, which is plumbed into the exhaust piping directly at the outlet of the turbocharger.

3. 3

   Wiring Repair (If Applicable)

   If the diagnostic tests revealed a short in the harness, splice and repair the damaged section of the High side supply #4 wire. Heat-shrink and re-loom the wire to protect it from future heat damage.

4. 4

   Actuator Replacement (If Applicable)

   Drain the engine coolant before removing the valve. Disconnect the electrical connector and the coolant lines attached to the actuator. Unbolt the exhaust clamps/flanges securing the valve to the turbocharger and exhaust pipe. Install the new exhaust brake valve assembly and torque the exhaust clamps to OEM spec. Reconnect the coolant lines and the electrical connector.

5. 5

   Refill Fluids

   Refill the engine cooling system with the appropriate coolant and bleed any air from the system.

6. 6

   Clear Codes

   Reconnect the battery, use a diagnostic service tool to clear the inactive 3354 fault code, and run the engine under load to verify that the SCR system heats up properly without triggering the code.