Case IH 433 – ENG (Engine Controller / Engine ECU): Boost Pressure level disagrees with engine operation conditions (speed & power)

The engine control system is detecting that the actual intake manifold boost pressure being generated by the turbocharger does not match the expected boost pressure target for the current engine RPM and engine load.

• MX Magnum
• STX Steiger
• Case IH Magnum series
• Case IH MX series (e.g., MX275, MX285)
• Case IH STX Steiger series (e.g., STX440)
• Case IH TG series
• Various Case IH Combines (e.g., Axial-Flow series)

1. 1

   Inspect for air leaks in the intake manifold, charge air piping, and exhaust system

2. 2

   Clean and inspect the Charge Air Cooler (CAC) for physical damage, restrictions, or pressure leaks

3. 3

   Check the turbocharger for axial clearance issues, compressor blade damage, and compressor seal leaks

4. 4

   Verify fuel pressure levels (low fuel pressure or a failing fuel pump can prevent the engine from generating enough exhaust gas to spool the turbocharger)

5. 5

   Inspect the Intake Manifold Pressure Sensor (Boost Pressure Sensor) and its wiring harness for shorts, open circuits, or incorrect data readings

1. 1

   Verify the Code

   Use the electronic service tool or the tractor's multi-function dashboard display to confirm Code 433 is active.

2. 2

   Visual & Smoke Test

   Perform a visual inspection of all turbocharger boots, clamps, and hoses. If no obvious tears are found, perform a pressurized smoke test on the intake system to locate hidden boost leaks. Repair or replace any leaking hoses or loose clamps.

3. 3

   Inspect the Turbocharger

   Remove the intake piping to the turbocharger and inspect the compressor wheel. Check for excessive shaft play (axial clearance) or oil leaks. If the turbocharger is damaged, it must be rebuilt or replaced.

4. 4

   Test the Sensor

   If the mechanical air and fuel systems are functioning correctly, test the Intake Manifold Pressure Sensor circuit. Check for a proper 5-volt reference, ground, and signal return to the Engine ECU.

5. 5

   Replace the Sensor

   If the wiring is intact but the sensor is reading out of range or providing erratic data, replace the Boost Pressure Sensor.

6. 6

   Clear and Road Test

   Clear the fault codes from the Engine ECU memory and operate the machine under a heavy load to verify that the boost pressure now matches the engine speed and power demands.