Lexus 89411-33010 Speed Sensor

The Vehicle Speed Sensor (VSS) is located on the transaxle and generates a voltage signal when it rotates. This signal is used by the PCM to control fuel, ignition, and transaxle shifting. To check the VSS, disconnect the connector and measure the voltage with a voltmeter. If no voltage, check for an open circuit. To further test, raise the front of the vehicle, secure it on jack stands, and block the rear wheels. Reconnect the connector and back probe with suitable probes. With the ignition on and engine off, manually rotate one wheel while holding the other steady. The voltmeter should display a pulsing voltage between zero and 11 volts. If not, replace the sensor by disconnecting the connector, removing the hold-down bolt, and pulling out the VSS. Replace the O-ring and reverse the installation.

Speed sensors are externally located on U241E, U140E, U140F, U150E, and U150F transaxle models, but internally mounted on U760E, U660E, U660F, U880F, U881E, U881F, UA80E, and UAB0F models. The Input Turbine Speed Sensor and Counter Gear Speed Sensor are on the transaxle. To replace, remove the battery and air intake duct, identify the sensor, disconnect its connector, and remove the mounting bolt. Discard the old sensor O-ring and use a new one during installation. Follow the removal steps in reverse to finish.

The Anti-lock Brake System (ABS) is designed to maintain vehicle steer ability, directional stability, and optimum deceleration under severe braking conditions and on most road surfaces. It does so by monitoring the rotational speed of each wheel and controlling the brake line pressure to prevent wheel lockup. The ABS system shares information with other optional systems, such as Electronic Brakeforce Distribution (EBO), Trac, and Vehicle Skid Control (VSC), to control vehicle handling. The actuator assembly, consisting of an electric hydraulic pump and solenoid valves, is responsible for providing hydraulic pressure and modulating brake line pressure. Speed sensors located at each wheel generate electrical pulsations indicating wheel rotational speed. The ABS computer processes information from the wheel speed sensors to control hydraulic line pressure and constantly monitors the system for faults. If a warning light comes on, preliminary checks can be performed, such as checking brake fluid level, verifying electrical connectors, checking fuses, and inspecting wiring connections. If the problem persists, the vehicle should be diagnosed and repaired by a qualified technician. Wheel speed sensors can be removed and installed by loosening lug nuts, raising the vehicle, disconnecting the electrical connector, removing the mounting bolt, and carefully pulling out the sensor. Installation is the reverse of the removal procedure.