Case IH 122 – Engine Controller (Engine ECU): Boost Pressure Sensor voltage is too high

The Engine Control Module (ECM) is receiving a voltage signal from the boost pressure sensor that exceeds the normal operating parameters. This typically triggers an engine de-rate to protect the system.

• MX Magnum
• STX Steiger
• TG Series
• Steiger
• Puma
• Maxxum series
• 7000 series
• 8000 series
• 9000 series
• 7010
• 7240
• 8240
• 9240

1. 1

   Inspect the wiring harness connecting the boost pressure sensor (intake manifold pressure sensor) to the ECM for visible damage.

2. 2

   Check the sensor and ECM connectors for damage, bent pins, loose connections, or corrosion.

3. 3

   Test the voltage at the sensor harness connector (specifically checking the signal pin and the 5-volt reference/supply pins) to confirm if the circuit is genuinely shorted to a high voltage source or if the sensor has failed internally.

1. 1

   Disconnect battery

   Disconnect the battery to prevent electrical spikes.

2. 2

   Locate sensor

   Locate the Boost Pressure Sensor (typically mounted on or near the intake manifold/charge air cooler piping).

3. 3

   Disconnect harness

   Disconnect the sensor harness.

4. 4

   Repair wiring

   If the diagnostic checks revealed damaged wiring or a short in the harness, repair the faulty wire or replace the affected harness section.

5. 5

   Remove sensor

   If the wiring tests within specification, the sensor itself has failed. Remove the retaining hardware and pull the old sensor out.

6. 6

   Install new sensor

   Install the new Boost Pressure Sensor (ensure the O-ring/seal is properly seated) and tighten to OEM torque specs.

7. 7

   Reconnect and clear codes

   Reconnect the harness, reconnect the battery, and clear the fault codes using a diagnostic tool.

8. 8

   Verify repair

   Run the engine to verify the code does not return and that engine power is restored.