Case IH 19409 – Engine Control Unit (ECU): High pressure intercooler outlet pressure sensor plausibility check low failure

The engine control system is running a plausibility check (comparing the sensor's reading against other known values like atmospheric pressure, intake manifold pressure, or turbocharger speed). A low failure means the sensor is reporting a pressure value that is implausibly lower than what the engine's operating conditions dictate. This typically points to a faulty sensor, a wiring issue (short to ground or high resistance), or a physical loss of charge-air pressure (a boost leak) after the high-pressure intercooler.

• Tier 4b
• Case IH 240 Series Axial-Flow Combines (7240, 8240, 9240)
• Other Case IH/New Holland high-horsepower tractors and sprayers sharing the same FPT Cursor/NEF engine architecture

1. 1

   Perform a Key-On, Engine-Off (KOEO) test using the diagnostic screen to check the sensor's pressure reading; it should match atmospheric pressure. A significantly lower reading points to a faulty sensor or wiring.

2. 2

   Visually inspect the high-pressure intercooler, charge-air cooler (CAC) piping, hoses, and clamps for soot trails, oil residue, blown boots, or loose clamps that indicate a physical boost leak.

3. 3

   Inspect the pigtail connector at the intercooler outlet pressure sensor for pushed-back pins, corrosion, or wire chafing.

4. 4

   Verify that the sensor is receiving the correct 5V reference and ground from the ECU.

1. 1

   Secure the Machine

   Park the machine on a level surface, lower all attachments, turn off the engine, and remove the key.

2. 2

   Address Physical Leaks (If Found)

   If the diagnostic check revealed a blown intercooler boot or loose clamp, re-seat the hose, replace the damaged boot, and torque the constant-tension clamps to OEM spec.

3. 3

   Replace the Sensor (If Faulty)

   Locate the high-pressure intercooler outlet pressure sensor (typically mounted on the charge-air piping exiting the intercooler or directly on the intake manifold, depending on the specific FPT engine variant). Disconnect the electrical harness connector. Unthread the sensor from the mounting port. Install the new sensor (ensure the O-ring or sealing washer is properly seated) and torque to specification. Reconnect the electrical harness.

4. 4

   Clear Codes

   Cycle the machine's power. Use the Case IH EST tool or the cab monitor diagnostic menu to clear the inactive 19409 / 2D93 fault code.

5. 5

   Test Run

   Start the engine and bring it to operating temperature. Run the engine under load to build boost and verify the code does not return.