Case IH 3772 – Engine Control Unit (ECU): Turbocharger : Over boost deviation at P2 too high in Pressure charger regulator.

This code indicates an overboost condition. The engine control system has detected that the actual turbocharger boost pressure (P2) is significantly higher than the commanded or expected target pressure. The turbocharger's wastegate actuator or the Electronic Variable Geometry Turbocharger (eVGT) actuator is failing to properly vent exhaust gases or adjust the turbine vanes to reduce boost pressure.

• Magnum MX215
• Magnum MX245
• Magnum MX275
• Magnum MX305
• Steiger
• Quadtrac
• Optum
• Puma
• Maxxum
• Farmall
• Axial-Flow 7240
• Axial-Flow 8240
• Axial-Flow 9240
• Axial-Flow 2388

1. 1

   Use the Case IH Electronic Service Tool (EST) to monitor the boost pressure sensor readings with the engine off (should read atmospheric pressure) and while running to verify if a skewed sensor is falsely reporting an overboost condition.

2. 2

   Physically inspect the linkage between the electronic actuator and the turbocharger wastegate or VGT vanes for binding, heavy soot buildup, or mechanical failure preventing free movement.

3. 3

   Check the wiring harness and connector at the turbocharger actuator for chafing, corrosion, or poor pin fitment, and perform an active sweep test using the EST to see if it responds to ECU commands.

4. 4

   Ensure there are no severe restrictions in the exhaust system, such as a plugged DPF or SCR, that could cause abnormal pressure dynamics.

1. 1

   Connect Diagnostic Tool

   Connect the EST to the machine's diagnostic port to confirm 3772 is the primary active code.

2. 2

   Test/Replace Boost Sensor

   If the boost pressure sensor is reading out of range during the diagnostic checks, locate the sensor on the intake manifold. Disconnect the harness, remove the sensor, and install a new OEM sensor.

3. 3

   Free Up Linkage

   If the actuator linkage is mechanically bound by soot or rust, apply penetrating oil and attempt to free the mechanism. If the internal VGT vanes are seized, the entire turbocharger assembly usually requires replacement.

4. 4

   Replace Actuator

   If the linkage moves freely but the actuator fails the EST sweep test (or has an internal electrical short), replace the wastegate/eVGT actuator. Note: On some newer FPT engines, the eVGT actuator is calibrated to the turbocharger at the factory and cannot be serviced separately; the entire turbo assembly must be replaced.

5. 5

   Re-calibration and Validation

   After replacing the actuator or turbocharger, use the EST to perform any required actuator calibration procedures. Clear the fault codes and test drive the machine under a heavy load to verify boost pressures remain within the target range.