Case IH 3794 – Engine Control Unit (ECU) / EDC (Electronic Diesel Control): Intake air pressure sensor: Plausibility Check for air pressure at the upstream of intake valve sensor

The Engine Control Unit (ECU) has detected an implausible reading from the Intake Air Pressure Sensor (also known as the Boost Pressure Sensor or MAP sensor). The signal is out of range, erratic, intermittent, or does not logically match the expected values (such as atmospheric pressure readings) for the current engine load and speed.

• Farmall
• skid steer
• Magnum
• Steiger
• Puma
• Maxxum
• 7010 series
• Skid Steers
• Compact Track Loaders

1. 1

   Connect a diagnostic tool to verify if the fault is currently active or stored in history.

2. 2

   Use the diagnostic tool to monitor live intake air/boost pressure readings. Look for erratic spikes, drop-outs, or a static reading that does not change with engine RPM.

3. 3

   Inspect the sensor port on the intake manifold to ensure it is clean and free of soot, carbon buildup, or debris that could block the sensor tip.

4. 4

   Check the sensor's electrical connector pins for corrosion, moisture, or damage.

5. 5

   Inspect the wiring harness leading to the sensor for chafing, shorts to ground, or open circuits.

1. 1

   Disconnect battery

   Turn off the engine, remove the key, and disconnect the battery to prevent electrical shorts.

2. 2

   Locate sensor

   Locate the Intake Air Pressure / Boost Pressure sensor on the engine. (On many FPT engines, such as those in the 7010 combine, it is located on the intake manifold just above the engine oil filter).

3. 3

   Disconnect harness

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

4. 4

   Remove fastener

   Remove the retaining fastener(s) holding the sensor to the manifold.

5. 5

   Remove sensor

   Pull the sensor straight out of its port.

6. 6

   Clean port

   Clean the mating surface and the sensor port on the manifold, ensuring no debris falls into the intake.

7. 7

   Install new sensor

   Lubricate the O-ring/rubber seal on the new sensor and press it firmly into the port.

8. 8

   Secure sensor

   Install and tighten the retaining fastener.

9. 9

   Reconnect harness

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

10. 10

    Clear codes and test

    Reconnect the battery, turn the key on, and use a diagnostic tool to clear the fault codes. Run the engine to confirm the code does not return.