Case IH 12627 – ABS (Anti-lock Braking System) Control Module or ATC (Automatic Temperature/Traction Control) Module: Front right wheel speed sensor - air gap

This fault indicates an issue with the physical clearance (the "air gap") between the front right wheel speed sensor and the tone ring. If the gap is too large, too small, or obstructed by debris or corrosion, the sensor cannot generate a valid, consistent signal, resulting in erratic, weak, or missing wheel speed data.

• Magnum
• Puma
• Steiger
• Optum
• 2000 Series Early Riser Planters

1. 1

   Connect a diagnostic scan tool and view live wheel speed data for all four wheels to verify if the front right speed reads zero, drops out, or is erratic

2. 2

   Inspect the front right sensor, wiring harness, and connector for mechanical damage, corrosion, or loose connections

3. 3

   Inspect the tone/reluctor ring on the hub/drive flange for damaged or missing teeth, heavy rust, or metallic debris attached to the magnetic encoder

4. 4

   Measure the air gap between the sensor tip and the tone ring using a feeler gauge and compare it to OEM specifications

5. 5

   Check for a damaged or loose front right wheel bearing, as excessive mechanical play will cause the tone ring to wobble and dynamically alter the air gap

6. 6

   Check for any source of Electromagnetic Interference (EMI) near the sensor wiring that could distort the signal frequency

1. 1

   Clean the Assembly

   If debris or metallic particles are present on the tone ring, clean it using a soft bristle brush or a mild detergent. Do not use a magnetic tool to remove debris, as this can permanently damage the magnetic encoder ring.

2. 2

   Address Mechanical Play

   If the wheel bearing is loose or failing, replace the hub bearing assembly, as a new sensor will not fix an air gap that fluctuates due to mechanical wobble.

3. 3

   Remove the Old Sensor

   Disconnect the electrical connector for the front right wheel speed sensor. Unbolt the sensor from its mounting point on the hub/knuckle.

4. 4

   Prep the Mounting Surface

   Thoroughly clean the sensor mounting surface. Any rust or dirt buildup under the sensor mounting tab will push the sensor outward, creating an air gap that is too large.

5. 5

   Install the New Sensor

   Install the replacement sensor and torque the mounting bolt to OEM specifications. Ensure it sits perfectly flush.

6. 6

   Reconnect Wiring

   Reconnect the electrical plug, ensuring the weather seal is intact. Use dielectric grease if appropriate to prevent moisture intrusion.

7. 7

   Clear and Test

   Clear the fault codes using a diagnostic tool. Perform a road test (exceeding 10 km/h) while monitoring live data to confirm the signal is restored and the code does not return.