New Holland ENG 3351 – Engine Controller (ENG / EDC / ECU): Engine Brake Decompression Valve - Open Load

The control module has detected a break in the electrical circuit that operates the engine brake decompression valve. This is typically caused by a disconnected wiring harness, a broken wire, corroded connector pins, or a burnt-out solenoid coil inside the valve itself.

• T8.xxx Series tractors (e.g., T8.275, T8.300, T8.390)
• Other New Holland/Case IH combine harvesters and heavy equipment utilizing the same FPT engine architecture

1. 1

   Locate the Engine Brake Decompression Valve on the engine and visually inspect the electrical connector and wiring harness for physical damage, chafing, or disconnected plugs.

2. 2

   Disconnect the valve's harness connector and inspect the pins for corrosion, moisture, or pushed-back terminals that could cause an open circuit.

3. 3

   Using a multimeter, measure the resistance across the pins of the Engine Brake Decompression Valve solenoid. If the reading shows infinite resistance (OL), the internal coil is burnt out.

4. 4

   If the valve's solenoid tests good, check the continuity of the wiring harness between the valve connector and the Engine ECU pins to locate any broken wires.

1. 1

   Disconnect Power

   Turn off the machine's ignition and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Repair Wiring

   If the diagnostic checks revealed a broken wire or damaged connector, splice in a new section of wire or replace the damaged connector pigtail.

3. 3

   Replace the Valve

   If the valve solenoid tested open (infinite resistance): Clean the area around the Engine Brake Decompression Valve to prevent debris from entering the engine. Disconnect the electrical harness. Unbolt and remove the faulty decompression valve. Install the new valve with a new O-ring/seal (lubricate the seal lightly with clean engine oil before installation). Torque the mounting bolts to OEM specifications. Reconnect the electrical harness securely.

4. 4

   Clear Codes and Test

   Reconnect the battery. Use a CNH Electronic Service Tool (EST) or a compatible diagnostic scanner to clear the inactive ENG 3351 fault code. Start the engine, bring it to operating temperature, and test the engine brake function to ensure the code does not return.