Case IH 3425 – ENGINE ECU: Turbocharger: Over boost deviation at P2 too high in pressure charger regulator

The engine is experiencing an overboost condition. The measured boost pressure (P2) has exceeded the maximum safe limit, and the turbocharger's pressure regulator (wastegate or variable geometry actuator) is failing to vent the excess exhaust drive pressure to bring the boost back into the commanded range.

• Farmall
• Case SR175
• Case SV250
• Case SV300

1. 1

   Check the Boost Pressure Sensor (P2) to verify that the sensor is not outputting a falsely high reading.

2. 2

   Inspect the Pressure Charger Regulator (turbocharger wastegate/governor actuator) for mechanical binding, carbon buildup, or failure to open.

3. 3

   Inspect the wiring harness and connectors between the Engine ECU (EDC) and the turbocharger regulator for shorts or open circuits.

1. 1

   Cool down machine

   Safely park the machine, turn off the engine, and allow the turbocharger assembly to cool completely.

2. 2

   Locate components

   Locate the turbocharger and the boost pressure sensor (P2) on the F5H engine.

3. 3

   Test and replace sensor

   Test the boost pressure sensor circuit. If the sensor is reading out of specification, replace the sensor.

4. 4

   Actuate regulator

   Manually actuate the turbocharger pressure regulator (wastegate linkage). If it is mechanically stuck closed (which causes the overboost deviation), attempt to free the linkage.

5. 5

   Replace turbocharger assembly

   If the regulator is electronically failed or mechanically seized and cannot be serviced separately from the housing, replace the entire turbocharger assembly.

6. 6

   Clear codes and test

   Reconnect all harnesses, clear the fault codes from the Engine ECU using a diagnostic tool, and run the machine under load to verify the overboost condition is resolved.