Case IH U18 – TCU / EDC: Correct Start Up Procedure Not Used

Fault code U18 is a procedural error indicating that the correct start-up sequence was not used when attempting to enter a calibration mode for the transmission, clutch, or rear electro-hydraulic remote valves. The electronic management system requires strict prerequisites to be met before calibration can begin. Alternatively, on certain models like the Puma or Steiger, if this code is triggered during normal operation rather than calibration, it indicates a short circuit in the front suspension pressure switch 1.

• Farmall
• Puma 165
• Puma 180
• Puma 195
• Puma 210
• Puma 225
• Magnum MX210
• Magnum MX230
• Magnum MX255
• Magnum MX285
• Steiger
• Maxxum

1. 1

   Ensure the tractor is completely stationary; any wheel movement will abort calibration

2. 2

   Ensure the parking brake is firmly applied

3. 3

   Check transmission oil temperature (must be warmed up above 10C/50F)

4. 4

   Verify lever positions; shuttle, main gear, and range levers must be in their correct starting positions (usually neutral)

5. 5

   Check engine RPM; throttle must be set correctly, typically between 1200 and 1250 ERPM

6. 6

   If the code appears during normal operation (not calibration) on Puma or Steiger models, check the front axle suspension pressure switch 1 for a short circuit

1. 1

   Prepare tractor

   Park the tractor on a level surface, apply the handbrake, and ensure the transmission fluid is at normal operating temperature.

2. 2

   Turn off ignition

   Turn the ignition key to the OFF position.

3. 3

   Enter calibration mode

   Press and hold both the upshift (Hi) and downshift (Lo) buttons simultaneously while starting the engine, or initiate using an electronic diagnostic tool.

4. 4

   Release buttons

   Once the display indicates that calibration mode is active, release the buttons.

5. 5

   Set engine speed

   Set the engine speed to the specified calibration RPM (typically around 1200 RPM).

6. 6

   Position levers

   Shift the shuttle lever to the Forward position (or leave remote levers in Neutral if calibrating EHR valves).

7. 7

   Execute calibration

   Follow the on-screen display prompts, using the up/downshift buttons to proceed through the clutch or synchronizer engagements.

8. 8

   Save configuration

   Once the display indicates calibration is complete, turn the ignition key OFF to store the new calibration configuration in the ECU memory.

9. 9

   Replace pressure switch

   If diagnosing the specific Puma/Steiger normal operation cause (not calibration), replace the Front Axle Suspension Pressure Switch if a short circuit is confirmed.