Case IH 3115 – Engine Control Module (ECM) / Vehicle Control Module (VCM): Boost Pressure Sensor (downstream) voltage is higher than expected.

The control module is receiving a voltage signal from the downstream boost pressure sensor that exceeds the maximum calibrated threshold. This condition typically points to a short circuit to a voltage source in the wiring harness, a failed sensor internally shorting, or a severely out-of-range pressure reading.

• 580N
• 580SN
• 580SN-WT
• 590SN
• TR270
• SV185
• SR175
• SR240

1. 1

   Inspect the wiring harness and the connector at the downstream boost pressure sensor for chafing, melted insulation, or exposed wires that could cause a short to battery voltage.

2. 2

   Disconnect the sensor and check the pins for corrosion, moisture, or damage.

3. 3

   With the key ON and engine OFF, probe the sensor connector to verify the 5V reference circuit and the ground circuit. If the signal wire shows 5V or 12V while disconnected from the sensor, there is a short to voltage in the harness.

4. 4

   Using a diagnostic scan tool, compare the atmospheric/ambient pressure sensor reading to the boost pressure sensor reading with the engine off. They should read nearly identical. If the boost pressure sensor reads artificially high, the sensor is likely defective.

1. 1

   Turn off the machine, remove the key, and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Locate the downstream boost pressure sensor (MAP sensor), typically mounted on the intake manifold or the charge air cooler piping.

3. 3

   Depress the locking tab and disconnect the electrical harness from the sensor.

4. 4

   Remove the mounting hardware (usually one or two small bolts) securing the sensor to the manifold.

5. 5

   Carefully pull the sensor out of its port.

   Inspect the port for heavy soot or carbon buildup and clean it gently if necessary, ensuring no debris falls into the intake.

6. 6

   Lubricate the O-ring on the new OEM boost pressure sensor with a small amount of clean engine oil.

7. 7

   Insert the new sensor into the port and tighten the mounting hardware to the manufacturer's torque specification.

8. 8

   Reconnect the electrical harness, ensuring it clicks securely into place.

9. 9

   Reconnect the negative battery cable.

10. 10

    Turn the key to the ON position and use a diagnostic scan tool to clear fault code 3115.

    Start the engine and verify that the code does not return and that the machine operates without derating.