Case IH 3025 (F-108-04) - ECU – Engine Control Unit (ECU / ECM): ECU internal failure - Ambient air pressure sensor voltage is lower than expected.

The barometric/ambient air pressure sensor, which is built directly into the circuit board of the control module, is registering a voltage signal that has dropped below the minimum acceptable threshold.

• VESTRUM CVX
• Farmall 40
• Farmall 45
• Farmall 50
• Farmall 120A
• Austoft A9000
• Austoft A9900
• Austoft A9990

1. 1

   Connect the Case IH Electronic Service Tool (EST) to confirm the code is active and not a stored historical anomaly. Clear the code, cycle the key, and see if it immediately returns.

2. 2

   Disconnect the main harnesses to the Engine ECU. Inspect the pins for corrosion, bent pins, or signs of water intrusion.

3. 3

   Verify that the ECU is receiving clean, stable battery voltage and has solid ground connections.

4. 4

   If the wiring, power, and grounds are perfect and the code remains active, the internal sensor has failed and the ECU must be replaced.

1. 1

   Power Down

   Turn off the ignition and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Locate the ECU

   Locate the Engine ECU (typically mounted directly to the side of the engine block on vibration isolators).

3. 3

   Disconnect Harnesses

   Carefully release the locking levers on the ECU wiring harness connectors and pull them straight out.

4. 4

   Remove the ECU

   Remove the mounting bolts securing the ECU to the engine block and remove the faulty module.

5. 5

   Install the New ECU

   Mount the replacement ECU and torque the bolts to OEM specifications.

6. 6

   Reconnect

   Reconnect the wiring harnesses, ensuring the locking levers click fully into place. Reconnect the negative battery cable.

7. 7

   Programming

   Connect the Case IH EST diagnostic laptop and flash the new ECU with the correct engine calibration software (dataset) specific to the machine's serial number and configuration.