Case IH 80 – TRANS (Transmission Controller): Wheel speed sensor is measured too high

The controller is receiving a frequency or voltage signal from the wheel speed (or transmission speed) sensor that exceeds the expected or plausible maximum limit for the vehicle's operating parameters. This is typically caused by a faulty sensor, a short to a high-voltage source in the wiring harness, or an instrumentation controller error.

• MX Magnum
• Case IH MX Series
• Case IH TG Series
• Case IH Magnum Series
• Case IH Steiger / Puma / Maxxum Series

1. 1

   Check for secondary codes (e.g., TRANS 3020, HITCH 3010, STEER 3010, or PTO 54060) as a failure here often triggers secondary CAN bus codes.

2. 2

   Observe the transmission state; a failed sensor typically forces the transmission into neutral as a safety precaution.

3. 3

   Inspect the wiring harness between the wheel speed sensor and the instrumentation controller, specifically looking for a short to power (+12v or +5v reference) which causes the high reading.

4. 4

   If equipped with radar, check for speed mismatch codes. If HITCH 3010 and PTO 54060 are not present, the radar gun may be the fault rather than the wheel speed sensor.

1. 1

   Park the tractor on a level surface, engage the parking brake, and turn off the engine.

2. 2

   Locate the wheel speed sensor.

   Depending on the tractor model, it is typically mounted on the transmission housing, rear axle housing, or final drive.

3. 3

   Disconnect the electrical connector from the sensor and inspect the pins for corrosion, moisture, or pushed-back terminals.

4. 4

   Clean the area around the sensor base thoroughly to prevent dirt from falling into the transmission/axle housing.

5. 5

   Remove the retaining bolt(s) securing the sensor.

6. 6

   Carefully pull the sensor out of its bore.

   Inspect the bore for burrs, metal shavings, or debris and clean if necessary.

7. 7

   Install the new wheel speed sensor and secure it with the retaining bolt.

8. 8

   Reconnect the electrical connector.

9. 9

   Turn the key on and use the tractor's diagnostic display (H-Menu) or a diagnostic tool (like Jaltest) to clear the stored fault codes.

10. 10

    Test drive the tractor to ensure the transmission shifts properly out of forced neutral, the speedometer reads accurately, and the fault code does not return.