Case IH TMF86 – TMF: Wheel Slip Signal Failure

The Tractor Multi-Function (TMF) / Instrumentation Controller has detected a failure in the wheel slip signal. This indicates a problem with the system that measures and reports the difference between the tractor's theoretical ground speed (calculated from transmission output) and its actual ground speed (measured by a radar sensor). A failure in this signal prevents accurate wheel slip percentage calculations, which can lead to inaccurate display readings and negatively affect the performance of automatic traction control systems and fuel efficiency.

• Magnum 180
• Magnum 225
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Magnum 380
• MX240
• MX255
• MX270
• MX285
• Puma 150
• Puma 165
• Puma 185
• Puma 200
• Puma 210
• Puma 220
• Puma 230
• Puma 240
• Maxxum 115
• Maxxum 125
• Maxxum 135
• Maxxum 145
• Maxxum 150

1. 1

   Visually inspect the wiring harness leading to the wheel speed sensors and the ground speed radar unit for chafing, cuts, or corrosion on the connectors

2. 2

   Check for intermittent faults by noting if the code appears under specific conditions (e.g., during turns, at certain speeds, or when moving slowly)

3. 3

   Perform a resistance check on the sensor pins using a multimeter and compare to specifications or a known good sensor (an 'open' or very high resistance indicates a failed sensor)

4. 4

   Test AC voltage output on passive sensors by spinning the wheel by hand; no voltage output suggests a faulty sensor

5. 5

   Check wiring continuity from the sensor harness to the controller, ensuring there are no breaks, shorts to ground, or shorts to other wires

1. 1

   Confirm the fault

   Use a diagnostic tool to read and clear the fault codes. Operate the tractor to see if the TMF86 code returns.

2. 2

   Isolate the faulty component

   Based on the diagnostic checks, determine if the issue lies with a wheel speed sensor, the ground speed radar, the wiring harness, or the Instrumentation Controller itself.

3. 3

   Repair or replace wiring

   If a wiring issue is found, repair the damaged section of the harness or replace the harness if the damage is extensive. Ensure all connections are clean and secure.

4. 4

   Replace the faulty sensor

   If a wheel speed sensor or radar is determined to be faulty, replace it with a new OEM or equivalent part.

5. 5

   Calibrate the system

   Use the instrument cluster display to set parameters for wheel slip calculation, as calibration is often necessary after replacing speed sensing components.

6. 6

   Final verification

   Clear any remaining fault codes and operate the tractor under various conditions to ensure the fault does not reappear and that the wheel slip information is accurate.