Toyota 83181-12020 Sensor, Speedometer

The anti-lock brake system, introduced in 1988, is designed to maintain vehicle steerability, directional stability, and optimum deceleration under severe braking conditions and on various road surfaces by monitoring the rotational speed of each wheel and controlling brake line pressure to prevent wheel lock-up. The actuator assembly includes the master cylinder, an electric hydraulic pump, and four solenoid valves, with the pump providing hydraulic pressure to charge the reservoirs that supply pressure to the braking system. Speed sensors located at each wheel generate electrical pulsations to indicate wheel rotational speed, with front sensors mounted to the brake backing plates on 1988 and 1989 models, while later models have sensor rings integrated with the outer Constant Velocity joint. Rear wheel sensors are bolted to the brake backing plates or axle carriers, with sensor rings integral to the rear hub assemblies. The ABS computer, mounted under the dashboard for earlier models and in the luggage compartment for later ones, processes information from the wheel speed sensors to control hydraulic line pressure and prevent wheel lock-up, while also monitoring the system for faults. If a problem arises, an "ANTI-LOCK" or "ABS" light will illuminate on the dashboard, and a diagnostic code will be stored for retrieval by a service technician. If the dashboard warning light remains on during operation, the ABS system needs attention, and while a special electronic ABS diagnostic tester is required for proper diagnosis, preliminary checks such as verifying brake fluid level, ensuring electrical connectors are secure, and checking fuses can be performed by a home mechanic before seeking professional repair.

Before its removal, ensure the functionality of the sensors by connecting the voltmeter to the sensor's multi-plug and isolate the other end of the multi-connector; Test with a digital meter with AC facility. Lift the vehicle to get to the relevant wheel and then unplug the wiring to the ABS sensor and then attach the meter. Adjust the wheel so that the output voltage is between 1.5 and 2.0 V may be done with the wheel; watch the AC output by observing the oscilloscope, which is an output voltage varies with the wheel speed. When the output of sensor is low or even zero, change the new sensor. Technique of measurement of the front wheel sensor is more demanding: hand brake, loosening of the front wheel nuts, raising of the car using the jack, and then removing the wheel. Loosen the mounting bolt fixing the sensor onto the hub and pull off the sensor using penetrating oil if required to get past the hardness of the two surfaces. If it does not require removal, then only disconnect the wiring of the sensor. Remove the bolt from the side of the tray just seen when unbolting the sensor wiring support bracket in the wheel arch and make your way to the grommet of the sensor wiring to locate the multi-plug and disconnect it. For the rear wheel sensor, the part is pressed into the rear hub of the car and requires a puller for removal and a press for installation; thus, it is best to consult a Toyota dealer owing to the costs and dangers involved. Refitting basically involves the following steps that are the opposite of the removal steps.

Refitting is done in reverse order of the removal procedure.

The first step is to disconnect the electrical connector from the VSS.

To replace the VSS, first remove the air filter housing. Then, disconnect the electrical connector from the VSS. After that, remove the VSS from the transaxle. Replace the 0-ring by removing the 0-ring from the speed sensor. Finally, installation is the reverse of removal.

Both sensors are located on the left side of the transmission. The input speed sensor is at the front end, near the bellhousing, while the output speed sensor is at the rear, on the extension housing (for 2WD models) or the front left corner of the transfer case (for 4WD models).

Before installing the new sensor, wrap the threads with Teflon sealing tape to prevent leakage and thread corrosion.

Hello! No, the gear is sold separately.