Case IH 12625 – ABS / TECU: Rear right wheel speed sensor - air gap

The physical distance (air gap) between the tip of the right rear wheel speed sensor and the tone ring (or gear teeth) it monitors is incorrect. An improper air gap prevents the sensor from reading the rotational speed accurately, resulting in a weak, erratic, or missing speed signal.

• Puma (140–240)
• Magnum (180–380)
• Maxxum (115–150)
• Farmall series

1. 1

   Check the right rear wheel speed sensor tip for a buildup of dirt, debris, or metal shavings that can alter the air gap.

2. 2

   Clean the connector thoroughly and inspect the wiring harness for cuts, chafing, or corrosion to verify it is not a poor electrical connection.

3. 3

   Inspect the tone wheel/gear inside the housing for damaged or missing teeth.

4. 4

   Check if the sensor has backed out or if the mounting bracket is loose, causing the air gap to widen.

1. 1

   Access the Sensor

   Locate the right rear wheel speed sensor on the rear axle housing.

2. 2

   Clean the Area

   Clean the sensor and its electrical connector thoroughly before disconnecting it to prevent dirt from entering the axle housing or the electrical pins.

3. 3

   Remove the Sensor

   Disconnect the wiring harness and unbolt/remove the faulty sensor.

4. 4

   Install the New Sensor

   Insert the new sensor into the housing.

5. 5

   Set the Air Gap

   Ensure the sensor is positioned with the proper air gap relative to the tone wheel.

6. 6

   Clear Codes

   Connect your diagnostic tool and clear the active/stored fault codes.

7. 7

   Test Operation

   Engage the tractor and drive it at various speeds to verify the sensor output is reading correctly and that the fault code does not return.