Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: System Description

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Steering / Power Assist Systems / Power Steering System(for Gasoline Model) / 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	Calculates the motor operation current based on the steering torque and vehicle speed signals, and outputs it to the motor. When a malfunction is detected in the power steering system, it outputs a warning signal to the combination meter assembly.
	Power Steering Motor	Generates power assist in accordance with the actuation current received from the power steering ECU. The built-in motor rotation angle sensor detects the rotation angle of the 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		Outputs the engine speed. Outputs the drive mode select signal.
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 (Electric Parking Brake Switch Assembly)		Switches the driving mode.

Problem Symptoms Table

System Diagram

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Toyota Avalon (XX50) 2019-2022 Service & Repair Manual > Front Camera System(for Hv Model): Lost Communication with TCM (U0101,U0123,U0129,U0142,U0293)
DESCRIPTION When a malfunction is detected between various ECUs and sensors, these DTCs are stored. DTC No. Detection Item DTC Detection Condition Trouble Area U0101 Lost Communication with TCM While the vehicle is being driven at 1 km/h or 1 mph or more, a communication error between the TCM (hybri ...

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: System Description

Problem Symptoms Table

System Diagram

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Toyota Avalon (XX50) 2019-2022 Owners Manual

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual