Case IH 12614 – ABS (Anti-lock Braking System) Control Module: Front left wheel speed sensor - shorted to ground

This indicates that the signal or power circuit for the front left ABS wheel speed sensor has a direct short to the chassis ground, preventing the controller from reading the wheel's rotational speed.

• Puma 170
• Puma 185
• Puma 200
• Puma 215
• Puma 230
• Puma CVT
• Maxxum series
• Magnum series

1. 1

   Visually inspect the wiring harness leading to the front left wheel speed sensor on the front axle for chafed insulation, pinched wires, or rubbing against the axle housing or steering components.

2. 2

   Perform a harness isolation test by disconnecting the sensor at the axle and using a multimeter to check the harness-side pins for continuity to ground.

3. 3

   Test the sensor internally with a multimeter to see if the sensor pins show continuity to the sensor's metal casing or mounting bracket.

4. 4

   Inspect the sensor and ABS module connectors for water ingress, mud, or corrosion which can bridge the pins to ground.

1. 1

   Preparation

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

2. 2

   Locate the Sensor

   Locate the front left wheel speed sensor, which is mounted on the front left axle hub/steering knuckle assembly.

3. 3

   Disconnect Wiring

   Unplug the electrical connector from the sensor. If the diagnostic checks proved the harness is shorted, trace the harness back to the ABS module, locate the chafed section, and repair the wiring using heat-shrink butt connectors or replace the harness section.

4. 4

   Remove the Sensor

   If the sensor is faulty, remove the retaining bolt holding the sensor to the hub.

5. 5

   Extraction

   Carefully pull the sensor straight out of its bore. If it is stuck due to rust or debris, use penetrating oil and gently twist it to avoid breaking the plastic sensor head inside the hub.

6. 6

   Clean the Bore

   Clean the sensor mounting surface and the bore to ensure the new sensor seats at the correct depth relative to the tone ring.

7. 7

   Installation

   Insert the new wheel speed sensor and tighten the retaining bolt to OEM torque specifications.

8. 8

   Reconnect and Secure

   Plug in the electrical connector. Ensure the wire is routed correctly and secured with cable ties (e.g., 193mm cable ties) to prevent it from rubbing against moving suspension or steering parts.

9. 9

   Clear Codes

   Turn the key on, use a diagnostic tool to clear the 12614 fault code, and test drive the tractor to verify that the ABS light stays off and wheel speed is registering correctly.