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 actuator 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 | |
|---|---|---|
| *: w/ Adaptive Variable Suspension System | ||
| 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 Actuator Assembly) | Sends the vehicle speed signal and steering coordinated control amount signal to the rack and pinion power steering gear assembly. | |
| ECM |
| |
| Air Conditioning Amplifier Assembly | Receives a signal from the power steering ECU (rack and pinion power steering gear assembly) to limit electrical usage. | |
| AVS ECU (Absorber Control ECU)* | Transmits the drive mode select signal to the power steering ECU assembly. | |
| 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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Customize Parameters
CUSTOMIZE PARAMETERS DRIVE MODE CUSTOMIZATION (w/ Adaptive Variable Suspension System) When the drive mode is switched to "CUSTOM" mode using the drive mode select switch (combination switch assembly)
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
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Inspection
INSPECTION PROCEDURE 1. INSPECT VACUUM SWITCHING VALVE (for Active Control Engine Mount System) (a) Measure the resistance. (1) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition 1 - 2 20°C (68°
Terminals Of Ecu
TERMINALS OF ECU CHECK INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY AND MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) (a) Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly. Click here (b) Measure the resistance according to the value(s) in the table
