Lexus ES: System Description
SYSTEM DESCRIPTION
DESCRIPTION
(a) The power steering ECU (rack and pinion power steering gear assembly) generates the necessary steering assist torque by calculating the steering assist force and controlling the motor current, based on the steering torque information from the torque sensor (rack and pinion power steering gear assembly), vehicle speed information from the skid control ECU (brake booster with master cylinder assembly), and information from the ECUs.
(b) When there is a drop in the power source voltage, the rear window defogger, windshield deicer, outer mirror heater, PTC heater and seat heater operations are limited as part of power steering system load control.
(c) When there is a drop in the power source that may require an increase in steering force, the system illuminates the power steering warning light in order to warn the driver.
Function of Components:| Component | Function | |
|---|---|---|
| Rack and Pinion Power Steering Gear Assembly HINT: The components listed on the right are built-in | Power Steering ECU |
|
| Power Steering Motor |
| |
| Torque Sensor | Detects the steering torque. | |
| Reduction Mechanism | Decelerates the motor rotation torque and transmits it to the rack shaft. | |
| Steering Sensor | Detects the steering angle and steering direction. | |
| Skid Control ECU (Brake Booster with Master Cylinder Assembly) | Sends the vehicle speed signal and steering coordinated control amount signal to the rack and pinion power steering gear assembly. | |
| Hybrid Vehicle Control ECU | Transmits the READY signal to the power steering ECU (rack and pinion power steering gear assembly). | |
| Air Conditioning Amplifier Assembly | Receives a signal from the power steering ECU (rack and pinion power steering gear assembly) to limit electrical usage. | |
| Combination Meter Assembly | EPS Warning Light | Illuminates to alert the driver when the power steering ECU (rack and pinion power steering gear assembly) detects a malfunction in the power steering system. |
| Multi-information Display | Displays a warning message to inform the driver of a malfunction in the system. | |
| Master Warning Light | Illuminates when a warning message is displayed on the multi-information display. | |
| Multi Buzzer | Sounds to warn the driver of a malfunction in the system. | |
| Forward Recognition Camera | Requests steering assist torque when the lane departure alert system judges that the vehicle is departing from its lane. | |
| Drive Mode Select Switch (Combination Switch Assembly) | Switches the driving mode. | |
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How To Proceed With Troubleshooting
CAUTION / NOTICE / HINT HINT:
Use the following procedure to troubleshoot the power steering system.
*: Use the Techstream.
PROCEDURE 1. VEHICLE BROUGHT TO WORKSHOP
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Calibration
CALIBRATION TORQUE SENSOR ZERO POINT CALIBRATION (USING TECHSTREAM) NOTICE: Perform torque sensor zero point calibration if any of the following conditions occur:
The rack and pinion power steering
Problem Symptoms Table
PROBLEM SYMPTOMS TABLE HINT:
Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of
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Precaution
PRECAUTION NOTICE: When disconnecting the cable from the negative (-) battery terminal, initialize the following systems after the terminal is reconnected. System Name See Procedure Lane Control System Pre-collision System Intelligent Clearance Sonar System Parking Assist
Removal
REMOVAL CAUTION / NOTICE / HINT The necessary procedures (adjustment, calibration, initialization or registration) that must be performed after parts are removed and installed, or replaced during sliding roof housing removal/installation are shown below. Necessary Procedure After Parts Removed/Insta
