Toyota 89413-24010 Sensor, Transmission Revolution

They include Anti-lock Brake System (ABS) and Vehicle Stability Control (VSC) which ensure that a car remains steerable, stable in its direction and experiences the best rate of deceleration when there is hard braking on different surfaces. ABS, on the other hand, regulates the brake line pressure and wheel rotation rate , to avoid wheel lock up during hard braking and VSC helps to correct over/under steer. The Traction Control System (TCS) complements these systems, so that its job is to limit wheel spin onto acceleration from slippery roads. An element of the master cylinder the modulator regulates hydraulic pressure to the brake calipers with an electric boost pump to provide pressure and solenoid valves for regulating brake line pressure during system operation. The system has a specific sensor for each wheel, that produces a signal proportional to the wheel's speed and an electronic processing module. Front sensors are installed in the steering knuckles, and the rear ones are fitted in the rear axle housing. The ABS/VSC/TCS computer receives data from the sensors to adjust hydraulic line pressure so that it does not lock a wheel or allow it to spin freely and also constantly searches for problems. In instances where a dashboard warning light stays on, the system needs service and initial diagnostics involve the integrity of brake fluid, wires, and fuses. If problems continue, then professional diagnosis as well as repairs are required, because those systems are complicated. For removal of wheel speed sensor, some of the steps include loosening of the lug nuts on the wheels with regard to the side where the speed sensor is fixed, lifting of the vehicle and after that disconnecting the electrical connector of the speed sensor, succeeding removal of the nut that holds the sensor to the vehicle chassis and a slow withdrawal of the speed sensor, with regard to fixing, the process involves the reverse of the above mentioned steps.

ABS is a system that is created to maintain the steerability, directionality and deceleration of the vehicle under severe braking forces and on most types of roads. It does this by watching how quickly each wheel spins around and managing brake line pressure to prevent them from locking up. The ABS system comprises the actuator assembly, which consists of the master cylinder, electric hydraulic pump, and four solenoid valves. The speed sensors are placed at each wheel and create electrical surges that indicate their rotational velocity. The ABS computer (ECU) is referred to as its "brain" found either under the dashboard or within the ABS actuator and it uses information given by wheel speed sensors to control hydraulic line pressure. These codes allow identification of malfunctions in the ABS system since they are stored in its computer. Whenever a problem occurs in the system, an ABS warning light will be illuminated and you can undertake certain processes so that you can search for these codes. After looking into it more deeply through diagnosing such trouble codes, jumping terminals on data link connector clears them out while depressing brake pedal repeatedly until they are overridden.

The VSS also known as Vehicle Speed Sensor which is located on the upper part of the transaxle is an electrical circuit part that create an oscillating voltage in the circuit as the shaft of the sensor turns. The PCM watches these voltage pulses to help control the fuel and ignition also transaxle shifting. To sort the VSS, the first step is to seize the electrical connection together with the sensor to be disconnected from the transaxle, next is the removal and replacement of the O-ring before reinstalling the VSS in the reverse order.

Above the transaxle, you will find the Vehicle Speed Sensor (VSS). This sensor is a piece of electronic equipment that produces a pulsating voltage whenever the sensor shaft rotates. The PCM then monitors these voltage pulses to help regulate the fuel and ignition systems as well as transaxle shifting. First, take off the air filter housing in order to replace it. After this, remove the electrical connector from VSS. At last, get rid of VSS from transaxle. Replace the 0-ring by removing the 0-ring from speed sensor. Finally, installation is just like removal.

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.

The coolant temperature sensor on four-cylinder engines is located on the rear of the cylinder head, while on the 3.0L V6 engine, it is found on the intake manifold beneath the air intake plenum at the rear, and on the 3.4L V6 engine, it is positioned behind the timing belt cover on the top of the intake manifold. Before installing a new sensor, wrap the threads with Teflon sealing tape to prevent leakage and corrosion. To remove the sensor, release the locking tab, unplug the electrical connector, and carefully unscrew it, taking care not to damage the sensor as it affects the fuel injection system. Install the new sensor quickly to minimize coolant loss and check the coolant level afterward. The Mass Airflow Sensor (MAF) is located on the air intake duct and measures the mass of air entering the engine; to replace it, disconnect the electrical connector, remove the air cleaner assembly, and lift the MAF sensor assembly from the air cleaner. The vane airflow sensor, found on 1993 and 1994 3.0L V6 engines, measures the volume of air entering the engine and is removed similarly. The Intake Air Temperature (IAT) sensor is located inside the air cleaner housing and is removed by unplugging the electrical connector and twisting it out of the rubber boot. Oxygen sensors, which monitor the oxygen content of exhaust gases, are located in the exhaust manifold or pipe; precautions include avoiding damage to the pigtail and ensuring air circulation to the sensor. Disconnect the battery before removing the oxygen sensor, and use anti-seize compound on the threads during installation. The Throttle Position Sensor (TPS) measures the throttle valve position and is located on the throttle body; it is removed by disconnecting the electrical connector and unscrewing it. The crankshaft position sensor is mounted in the timing cover for four-cylinder engines and on the oil pump for 3.4L V6 models, while the camshaft position sensor is located above the intake manifold for four-cylinder models and behind the timing belt cover for 3.4L V6 models. Knock sensors, located below the intake manifold, control spark knock by retarding ignition timing and require coolant drainage for access. The Vehicle Speed Sensor (VSS) is found at the rear of the transmission housing and sends a voltage signal to the ECM. Lastly, the EGR gas temperature sensor, mounted near the EGA valve, detects exhaust temperature and regulates EGA on/off time efficiently.

The sensors in the U250E 5-speed transaxle are for measuring the speed of the turbine (input) shaft and the counter gear (output) shaft.

The input speed sensor is located on the left side of the transmission, while the output speed sensor is located on the right side. The location of the output speed sensor is the same for both 2WD and 4WD models.

After removing the VSS, you should replace the O-ring.

Complete the replacement process by following the removal steps in reverse order. This entails reattaching the speed sensor, securing the mounting bolt, connecting the electrical connector, and finalizing any other steps in the reverse sequence.

The ABS is designed to maintain vehicle steerability, directional stability, and optimum deceleration under severe braking conditions and on most road surfaces. It achieves this by monitoring the rotational speed of each wheel and controlling the brake line pressure to prevent wheel lock-up.