Wheel Speed Signal Conditioner Module

The wheel speed signal conditioner module for the L81 application is only equipped on vehicles without antilock brakes. The wheel speed conditioner module is located under the driver side I/P, which is orange in color and similar dimensionally to a relay. The module harness is tied to the I/P harness.

Vehicle speed on non-ABS vehicles is received from the right front wheel speed sensor. The wheel speed signal conditioner module is used to convert the AC voltage to the sensor to a square wave. This is accomplished by Pulse Width Modulating (PWM) the VSS output circuit to ground, which is pulled up to 5 volts through resistance in the ECM. The ECM interprets the square wave input as vehicle speed.