GM 20938122
ABS Sensor, Rear

Start the replacement process by lifting up your vehicle and putting it in a stable position. Unplug the power source and take out the wheel speed sensor bolt. Detach the wheel speed sensor wiring clips from their retainers before taking out the wheel speed sensor. Turn the wheel speed sensor clockwise until it reaches full insertion then install and tighten its bolt to 13 N.m at 115 lb inch torque setting. Plug in the electrical connector and route the wheel speed sensor wiring harness to its retainers before letting the vehicle down to the ground. Start the engine and let it run to test the wheel speed sensor using the ABS or traction assist light for verification. Drive the vehicle only after professional diagnosis and wheel speed sensor connector assessment. Check Symptoms of Antilock Brake System problems when the warning lamp stays lit. Choose a straight area without debris or traffic and drive the vehicle steadily at 16 km/h (10 mph) or more for 5 seconds. When done check if the ABS or traction assist indicator appears; call Diagnostic Starting Point - Antilock Brake System for help.

A vehicle with less than 3900 kg (8600 lb) gvw requires a two-step process to switch the rear Wheel Speed Sensor ring. Lift and stabilize the vehicle followed by tire and wheel assembly removal. You need to remove the rear Wheel Speed Sensor and the axle housing cover first before proceeding. Remove the Axle Shaft using j 45857 and j 2619-01 before taking out the Axle Shaft seal and bearing plus Wheel Speed Sensor ring from the axle housing. Use j 45860 and j 8092 to put the new Wheel Speed Sensor ring into the axle housing until it meets the housing tube. Use duo-set j 23690 and j 8092 to drive the Axle Shaft bearing into position until the tool hits the tube when installing. To install the Axle Shaft seal put the j 21128 tool into the bore and push it until the seal surface touches the tube. Place the shaft inside then put back the rear axle housing cover and install the rear Wheel Speed Sensor. Reinstall the wheel and tire parts before putting required differential oil into the rear axle and lowering the vehicle.

Support the vehicle correctly before replacing the rear Wheel Speed Sensor on vehicles more than 8600 pounds gross vehicle weight. Detach the Wheel Speed Sensor electrical connection and secure the electricity connection before taking off the inboard frame rail clips. Extract the Wheel Speed Sensor bolt before you remove the Wheel Speed Sensor from the rear axle position. You must fit the new Wheel Speed Sensor onto the rear axle and tighten the Wheel Speed Sensor bolt 9 nm (80 lb in). Connect the Wheel Speed Sensor electrical connector back and push the electrical clip against the inboard frame rail at its secure position. Confirm system operation with a vehicle diagnostic system test at the end.

The procedure starts with lifting and supporting the vehicle to work on models with gvw above or at 3900 kg (8600 lb). To start the replacement disconnect the Wheel Speed Sensor electrical connector then release its connector and harness electrical holder from the inboard frame rail. Lift out the Wheel Speed Sensor after you remove its bolt near the wheels. Mount the Wheel Speed Sensor onto the rear axle by placing it in position and secure the Wheel Speed Sensor bolt with a 9 nm (80 lb in) torque value. Connect the Wheel Speed Sensor electrical connector back and fix the electrical connector and sensor harness to the inboard frame rail. Perform either diagnostic system check - vehicle (with HP2) or diagnostic system check - vehicle (without HP2) as the final step.

Install the WSS into the hub/bearing assembly, ensuring it is fully seated, and then install the WSS mounting bolt, tightening it to 18 N.m (13 lb ft).

Check if the ABS indicator or the traction assist indicator is illuminated; if so, follow the diagnostic starting point for the Antilock Brake System.

Plug the bore to prevent debris from entering the hub, clean the mounting surface with a wire brush, and apply a thin layer of the lubricant supplied in the WSS kit to the hub surface and the WSS O-ring.