Case IH 12633 – ABS Control Module / TECU: Rear right wheel speed sensor - damaged sensor ring

The rear right wheel speed sensor ring is physically damaged, heavily corroded, or missing teeth, preventing the sensor from reading pulses correctly to determine wheel speed and deceleration.

• Case IH Puma 150
• Case IH Puma 165
• Case IH Puma 185
• Case IH Puma 200
• Case IH Puma 210
• Case IH Puma 220
• Case IH Puma 240
• Case IH Puma CVX
• Case IH Optum
• Case IH Magnum

1. 1

   Remove the rear right wheel speed sensor and inspect the tip for metal shavings or debris that might be interfering with the magnetic signal.

2. 2

   Shine a light into the sensor mounting hole and slowly rotate the rear right wheel. Look for missing teeth, cracks in the ring, or heavy rust blocking the notches.

3. 3

   Ensure the gap between the wheel speed sensor and the tone ring is within factory specifications, as an improper gap can mimic a damaged ring.

4. 4

   Check the wheel speed sensor wiring harness and connectors for open circuits, short circuits, or corrosion to rule out electrical failure.

1. 1

   Preparation

   Park the tractor on a hard, level surface. Engage the parking brake, chock the front wheels, and safely lift and support the rear right axle.

2. 2

   Drain fluids

   If your model requires removing the rear trumpet housing to access the inner hub, drain the rear axle/transmission oil into a clean container.

3. 3

   Disconnect electronics

   Disconnect the electrical connector for the right-hand rear wheel speed sensor.

4. 4

   Disassembly

   Remove the rear right wheel. Depending on the specific axle configuration (bar axle vs. flange), remove the brake components and unbolt the rear axle trumpet housing/hub assembly to access the internal sensor ring.

5. 5

   Remove the damaged ring

   Carefully pry or use a chisel/punch to remove the damaged ABS reluctor ring from the hub.

6. 6

   Clean the hub

   Thoroughly clean the mounting surface on the hub with a wire brush to remove all rust and debris. A clean surface is critical to prevent the new ring from cracking during installation.

7. 7

   Install the new ring

   Press-fit the new ABS sensor ring onto the hub.

8. 8

   Reassembly

   Reassemble the axle housing, reinstall the wheel speed sensor, and reconnect the wiring harness.

9. 9

   Final steps

   Refill the transmission/axle oil, mount the wheel, clear the fault codes from the ECU, and test drive to verify the ABS light stays off and speed registers correctly.