Case IH 124 – Engine Controller (ENG) / Engine ECU: Boost Pressure level has exceeded the warning limit

The Intake Manifold Pressure Sensor is reading data that is valid but above the normal operational range. The intake manifold pressure has exceeded the maximum safe limit for the given engine rating, which typically forces the engine into a power derate mode to prevent mechanical damage.

• MX Magnum
• STX Steiger
• Case IH MX Magnum series
• Case IH STX Steiger series (STX440, STX500, STX550)
• Case IH Maxxum series (MXM120, MXM130, MXM140, MXM155, MXM175, MXM190)
• Case IH MXU series (MXU110, MXU125, MXU135)
• Case IH Axial-Flow Combines (5130, 6130)
• Case IH WDX1902
• Case IH WDX2302

1. 1

   Inspect Hoses and Connectors: Check the turbocharger boost hoses and charge air cooler (CAC) piping for blockages, restrictions, or physical damage.

2. 2

   Wiring and Circuit Check: Inspect the boost pressure sensor's 4-pin electrical connector and wiring harness for shorts to ground, corrosion, or loose connections.

3. 3

   Sensor Plausibility: Verify if the boost pressure sensor reading is plausible compared to the atmospheric pressure sensor when the engine is off (they should read nearly identical values at rest).

4. 4

   Mechanical Overboost Check: Ensure the turbocharger wastegate (if equipped) is not stuck closed, which would cause a genuine mechanical overboost condition rather than a sensor failure.

1. 1

   Turn off the engine, remove the key, and allow the engine and exhaust components to cool completely.

2. 2

   Locate the Boost Pressure / Intake Manifold Air Temperature Sensor, which is mounted directly on the intake manifold.

3. 3

   Disconnect the 4-pin electrical harness from the sensor. Inspect the harness for any dirt or bent pins and clean it with contact cleaner if necessary.

4. 4

   If the wiring and intake hoses are confirmed to be in good working order, the sensor itself has likely failed or drifted out of calibration. Remove the retaining hardware and pull the faulty boost pressure sensor from the manifold.

5. 5

   Install the replacement OEM boost pressure sensor. Ensure the O-ring is properly seated to prevent boost leaks.

6. 6

   Reconnect the electrical harness.

7. 7

   Use a diagnostic tool to clear the inactive fault codes from the Engine ECU.

8. 8

   Start the engine and run the machine under load to verify that boost pressure remains within normal operating limits and Fault Code 124 does not return.