ABS Wheel Speed Sensor - Front

This procedure covers the removal and replacement of the front ABS wheel speed sensor on a 2007 Ram 3500 with 5.9L Cummins diesel and 4WD.

Warnings

Tools required

Parts

• Front ABS wheel speed sensor × 1 — Use OEM Mopar specification
• Dielectric grease × 1 — Small packet

Preparation

1. Park vehicle on level ground and engage parking brake
2. Place wheel chocks behind rear wheels
3. If replacing left front sensor, turn steering wheel fully to the right; if replacing right front sensor, turn steering wheel fully to the left for better access
4. Loosen lug nuts on the wheel where sensor is being replaced while vehicle is on ground
5. Raise front of vehicle with floor jack and support securely on jack stands under frame rails
6. Remove wheel and tire assembly

Procedure

1. 1

   Locate the ABS wheel speed sensor
   The front wheel speed sensor is mounted at the front axle hub/knuckle assembly. On this solid-front-axle truck the sensor is retained at the wheel end near the hub bearing. Trace the sensor wire from the sensor up toward the frame rail where it connects to the vehicle harness, noting the routing and any clips or brackets securing it. Trace the sensor wire from the back of the knuckle up toward the frame rail where it connects to the vehicle harness. Note the routing of the wire and any clips or brackets securing it.
2. 2

   Disconnect the sensor electrical connector
   Follow the sensor wire harness up from the sensor to locate the electrical connector, typically found near the inner fender or frame rail. Press the locking tab and disconnect the connector. If the connector is corroded or difficult to separate, use a small screwdriver to carefully release the locking tab while pulling the connector halves apart.
3. 3

   Release wire harness routing clips
   Carefully release the sensor wire from all routing clips and brackets along its path from the sensor to the connector. Use a pick tool or small screwdriver to release clip retainers. Note the exact routing for reinstallation. On some vehicles, plastic clips may be brittle and break during removal; have replacements ready if needed.
4. 4

   Apply penetrating oil to sensor mounting bolt
   Spray penetrating oil around the sensor mounting bolt and the sensor body where it enters the knuckle. Allow 5-10 minutes for penetration. This is especially important on vehicles exposed to road salt and corrosion. Verify the sensor mounting bolt head size before starting; it is commonly a small metric hex head but confirm against the Mopar service manual for this vehicle.
5. 5

   Remove sensor mounting bolt
   Using the correct-size socket or wrench (verify size in the Mopar service manual), remove the single bolt securing the sensor to the axle hub/knuckle. If the bolt is severely corroded, be careful not to round off the head. Use a six-point socket and apply steady pressure. Keep the bolt if it is in good condition for potential reuse.
6. 6

   Extract the wheel speed sensor
   Carefully pull the sensor straight out of the knuckle bore. The sensor may be tight due to corrosion or debris buildup. Gently wiggle and rotate while pulling if needed. Do not pry against the sensor tip or use excessive force as this can damage the tone ring on the hub bearing. If extremely stuck, apply more penetrating oil and allow additional soak time.
7. 7

   Clean the sensor mounting bore
   Use a wire brush to thoroughly clean the sensor mounting bore in the steering knuckle. Remove all rust, dirt, and debris. The bore must be clean to ensure proper sensor seating and accurate air gap. Wipe clean with a rag. Inspect the tone ring (toothed reluctor ring) on the hub bearing for damage, missing teeth, or debris.
8. 8

   Prepare new sensor for installation
   Inspect the new sensor to ensure it matches the original. Apply a thin coat of dielectric grease to the O-ring on the sensor body. Do not apply grease to the sensor tip. Compare the wire harness routing and connector type to ensure correct part.
9. 9

   Install new wheel speed sensor
   Carefully insert the new sensor straight into the knuckle bore, ensuring it seats fully. The sensor should slide in smoothly if the bore is clean. Install the mounting bolt and tighten by hand initially. Tighten the mounting bolt to the Mopar-specified torque for this vehicle's front wheel speed sensor bolt (verify in the service manual); do not over-torque, as the sensor housing can crack.
10. 10

    Route and secure sensor wire harness
    Route the sensor wire harness following the original path, ensuring it does not contact any moving parts, hot components, or sharp edges. Secure the harness with all original clips and brackets. The wire must have adequate slack to allow for suspension movement and steering travel without stretching or binding.
11. 11

    Reconnect electrical connector
    Apply a small amount of dielectric grease to the terminals inside both connector halves to prevent corrosion. Connect the sensor harness to the vehicle harness, ensuring the connector locks securely with an audible click. Gently tug on the connection to verify it is fully engaged.
12. 12

    Reinstall wheel and tire
    Reinstall the wheel and tire assembly. Thread all lug nuts by hand to prevent cross-threading. Tighten lug nuts in a star pattern to the Mopar-specified torque for this vehicle (verify exact value in the owner's manual/service manual, as 3500 SRW and DRW specs differ). Lower vehicle from jack stands and perform final lug nut torque check with wheels on ground.

Reassembly

1. Ensure all wire harness routing clips are securely fastened and the harness has adequate slack for suspension and steering movement
2. Verify the electrical connector is fully locked and weather seal is properly seated
3. Double-check that lug nuts are torqued to specification in a star pattern

Verification

• Start the engine and verify the ABS warning light performs a normal bulb check (illuminates briefly then goes out)
• If a scan tool is available, check for ABS codes and verify the new sensor is reading properly with no stored or active faults
• Test drive the vehicle at speeds above 10-15 mph to allow the ABS system to verify sensor operation; the ABS light should remain off
• Perform a gentle brake test in a safe area to confirm ABS functionality if conditions allow
• Re-check lug nut torque after 50-100 miles of driving

Related trouble codes on this vehicle

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