Case IH 298 – Engine Control Module (ECM) / ENG: OEM Pressure Sensor Voltage is too low

The Engine Control Module (ECM) has detected that the signal voltage from the Original Equipment Manufacturer (OEM) auxiliary pressure sensor circuit has dropped below the acceptable range (out of range low). This is typically caused by a low signal voltage, an open circuit, or a short to ground in the OEM pressure circuit.

• MX Magnum
• STX Steiger
• Case IH Magnum Tractors (N.A. Models 215, 245, 275, 305, 335 and EU Models 225, 250, 280, 310, 335)
• Case IH STX Steiger Tractors (Models 350 through 600)
• Equipment running Cummins engines (QSB, QSC, QSL, QSM11, QSX15, QSK19, ISX, X11, X12, X13)

1. 1

   Check the engine wiring harness leading to the OEM pressure sensor for physical damage, chafing, or melted insulation.

2. 2

   Disconnect the sensor and inspect the pins for corrosion, moisture, or pushed-back terminals that could cause an open circuit.

3. 3

   Test the signal circuit to see if it is open or shorted to ground in the engine harness or at the sensor itself.

4. 4

   Test the supply wire to ensure it is providing the correct reference voltage and is not open or shorted to ground.

1. 1

   Locate the Sensor

   The exact location of the OEM pressure sensor varies depending on the specific engine model and chassis configuration (refer to your specific machine's service manual for the exact block or auxiliary port location).

2. 2

   Disconnect and Inspect

   Turn the keyswitch OFF. Disconnect the OEM pressure sensor harness connector. Clean the connector if dirt or oil is present.

3. 3

   Test the Wiring

   Using a multimeter, verify that the sensor is receiving the proper supply voltage from the ECM. Check for continuity on the signal wire back to the ECM harness.

4. 4

   Replace the Sensor

   If the wiring harness and supply voltage test good (no shorts to ground or open wires), the sensor itself has failed internally and is pulling the voltage low. Remove the old sensor and install the replacement.

5. 5

   Validate the Repair

   Perform a key cycle, start the engine, and let it idle for 1 minute. The fault code status on your electronic service tool or dash should change to INACTIVE, and the amber CHECK ENGINE lamp will turn off. You can then use the 'Reset All Faults' command to clear the inactive code from the ECM history.