New Holland ENG 393 – Engine Controller: Engine Brake driver 3 circuit failure

Indicates an electrical fault—such as an open circuit, a short to ground, or a short to battery voltage—within the circuit that controls the #3 engine brake driver (solenoid/decompression valve).

• T7 Series
• T7.270
• T8000 Series
• T8040
• T8 Series
• CR9090
• CX8080 Elevation
• CX8090 Elevation
• FR450 Forage Harvester
• Magnum Series
• Magnum 215
• Magnum 245
• Magnum 275
• Magnum 305
• Magnum 335

1. 1

   Inspect the wiring harness running from the Engine Controller (ECM) to the #3 engine brake solenoid for chafed wires, melted insulation, or pinched lines

2. 2

   Disconnect the harness at the #3 engine brake solenoid and at the ECM to check for pushed pins, corrosion, or moisture inside the connectors

3. 3

   Measure the resistance of the #3 engine brake solenoid using a multimeter to determine if the coil has failed open or shorted internally

4. 4

   Check the harness for continuity end-to-end, and verify there is no continuity to ground where there shouldn't be

1. 1

   Power Down

   Turn off the machine and disconnect the battery to prevent electrical spikes.

2. 2

   Access the Solenoid

   Depending on the engine model (FPT or Cummins), remove the engine valve cover or engine brake housing to access the engine brake solenoids.

3. 3

   Repair Wiring

   If the diagnostic checks revealed a broken or shorted wire in the harness, repair the wire using OEM-approved splicing techniques or replace the affected harness section.

4. 4

   Replace the Solenoid

   If the wiring is intact but the #3 solenoid failed the resistance test, unbolt the faulty engine brake solenoid, remove any sealing washers/O-rings, and install the new solenoid. Torque to OEM specifications.

5. 5

   Reassembly

   Reinstall the valve cover/housing with a new gasket.

6. 6

   Clear and Test

   Reconnect the battery, clear the ENG 393 fault code using a diagnostic tool, and test-run the engine/engine brake to ensure the code does not return.