Lexus NX: System Description
SYSTEM DESCRIPTION
- The power steering system generates torque through the operation of the motor and the reduction gear installed on the column shaft in order to assist steering effort.
- The power steering ECU assembly determines the direction and amount of assist power in accordance with vehicle speed signals and signals from the torque sensor built into the electric power steering column sub-assembly. As a result, the power steering ECU assembly adjusts the steering effort so that it is lighter during low speed driving and heavier during high speed driving.
DESCRIPTION
(a) Power steering ECU assembly:
The power steering ECU assembly calculates assist power based on steering torque signals from the torque sensor and vehicle speed signals from the skid control ECU.
(b) Torque sensor:
The torque sensor detects the steering effort generated when the steering wheel is turned and converts it to an electrical signal.
(c) Power steering motor:
The power steering motor is activated by the current from the power steering ECU assembly and generates torque to assist the steering effort.
(d) Motor rotation angle sensor:
The motor rotation angle sensor consists of a resolver sensor, which excels in reliability and durability. The rotation angle sensor detects the rotation angle of the motor and sends it to the power steering ECU assembly. As a result, it ensures efficient power steering control.
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How To Proceed With Troubleshooting
CAUTION / NOTICE / HINT HINT:
Use these procedures 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 THE Techstream) NOTICE: Perform torque sensor zero point calibration if any of the following conditions occur:
The power steering ECU assembl
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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Vehicle Speed Signal (C1541)
DESCRIPTION The power steering ECU assembly receives vehicle speed signals from the skid control ECU via CAN communication. The ECU provides appropriate assisting force in accordance with the vehicle speed based on the signals. DTC No. Detection Item DTC Detection Condition Trouble Area W
Generator Inverter Performance (P0A7A-325,P0A7A-810)
DTC SUMMARY MALFUNCTION DESCRIPTION These DTCs indicate that a large current flowed in the inverter for the generator. The cause of this malfunction may be one of the following: Internal inverter malfunction
Internal circuit malfunction in the inverter for the generator
Malfunction in the senso
