Case IH 19408 – Engine Control Unit (ECU): High pressure intercooler outlet pressure sensor plausibility check high failure

This fault code indicates that the pressure reading coming from the high-pressure intercooler outlet pressure sensor is implausibly high. The Engine Control Unit (ECU) runs a plausibility check by comparing this sensor's output to other related sensors. A high failure means the sensor is reporting a voltage or pressure value that is higher than physically possible for the current engine operating conditions, which typically points to a short circuit to a high voltage source, a skewed sensor, or a severe restriction in the charge air system.

• Tier 4b
• Case IH 240 Series Axial-Flow Combines (7240, 8240, 9240)
• Case IH Puma
• Case IH Magnum
• Case IH Steiger
• Case IH Optum

1. 1

   Perform a Key-On, Engine-Off (KOEO) test using a diagnostic scan tool to read the high-pressure intercooler outlet pressure. It should match ambient barometric pressure; if significantly higher, the sensor is likely skewed or shorted.

2. 2

   Inspect the sensor's electrical connector and wiring harness for rubbed wires, corrosion, pin damage, or a short circuit to a 5V reference or 12V power wire.

3. 3

   Physically inspect the intercooler and charge air piping for severe blockages or restrictions that could cause an actual overpressure condition.

4. 4

   Remove the sensor and ensure the mounting port is not packed with soot, oil, or debris, which can trap pressure against the sensor diaphragm.

1. 1

   Power Down

   Turn off the machine, remove the key, and allow the engine and charge air cooler piping to cool completely.

2. 2

   Locate the Sensor

   Locate the high-pressure intercooler outlet pressure sensor, which is mounted on the charge air piping between the intercooler outlet and the intake manifold.

3. 3

   Disconnect Harness

   Carefully depress the locking tab and disconnect the electrical harness from the sensor.

4. 4

   Remove Sensor

   Unbolt or unthread the faulty sensor from the intercooler piping.

5. 5

   Clean and Inspect

   Wipe the mounting port clean. Ensure no debris falls into the intake tract.

6. 6

   Install New Sensor

   Install the replacement sensor. If it is a threaded sensor, tighten to the OEM torque specification. If it uses an O-ring and retaining bolt, ensure the O-ring is lubricated lightly with clean engine oil before seating.

7. 7

   Reconnect

   Plug the electrical harness back in until it clicks securely.

8. 8

   Clear Codes

   Turn the key on and use a diagnostic tool to clear the 19408 fault code.

9. 9

   Test Run

   Start the engine and monitor the intercooler pressure parameters to ensure they are now reading within a plausible range.