New Holland ENG 3425 – Engine Control Unit (ECU) / EDC7: Turbocharger: Over boost deviation at P2 too high in pressure charger regulator.

The Engine Control Unit (ECU) has detected that the turbocharger boost pressure has exceeded the maximum allowable limit for a continuous period greater than 5.0 seconds. This indicates that the engine is experiencing an over-boost condition, or the ECU is receiving an inaccurate (falsely high) reading from the boost pressure sensor.

• T6 Series (e.g., T6.120 - T6.175)
• T7 Series (e.g., T7.170 - T7.315 Heavy Duty)
• T8 Series (e.g., T8.320 - T8.435)
• T9 Series
• W50C ZB
• W60C ZB
• W70C HS
• W70C
• W80C HS
• W80C
• L Series
• C Series (e.g., L465, Lx465, Lx485)

1. 1

   Use the Electronic Service Tool (EST) to verify if the fault code is currently present and active. If inactive/stored, clear it and test the machine.

2. 2

   Check for associated active faults related to the boost pressure sensor (voltage/circuit codes) or the EVGT actuator (codes 3858 through 3868). Diagnose and correct these first.

3. 3

   Inspect the wiring harness between the Engine ECU, the boost pressure sensor, and the EVGT actuator for chafing, shorts to ground, or open circuits.

4. 4

   Inspect the EVGT linkage to ensure it is not disconnected, damaged, sticking, or blocked by carbon buildup. For wastegate models, check the wastegate linkage for binding.

1. 1

   Repair Wiring

   If the diagnostic checks reveal damaged wiring between the ECU and the boost pressure sensor/eVGT actuator, repair or replace the affected harness section.

2. 2

   Clean/Replace Boost Pressure Sensor

   If the wiring is intact but the ECU is receiving inaccurate pressure readings, remove the boost pressure (MAP) sensor. Check for heavy soot or carbon blockage at the sensor port. If cleaning does not restore accurate readings, replace the boost pressure sensor.

3. 3

   Free or Replace the EVGT Actuator

   If the boost sensor is reading accurately but the turbo is physically over-boosting, the EVGT actuator is likely stuck in the 'vanes closed' (high boost) position. Attempt to manually actuate the linkage. If the linkage is seized internally within the turbocharger, the turbocharger assembly must be cleaned or replaced. If the electronic actuator itself has failed internally, replace the actuator.

4. 4

   ECU Software/Hardware

   If the sensor, actuator, and wiring all test perfectly, the fault may lie with the ECU software (requires a re-flash via the EST) or an internal ECU hardware failure.

5. 5

   Final Validation

   Clear the ENG 3425 code using the EST. Run the machine under a heavy load to ensure the boost pressure regulates properly and the code does not return.