Electronic Power Steering System Ig Power Source Circuit

Steering. Lexus Gs430, Gs300. Uzs190 Grs190
Power Steering. Lexus Gs430, Gs300. Uzs190 Grs190

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK HARNESS AND CONNECTOR

INSPECT CAN COMMUNICATION SYSTEM

INSPECT MULTIPLEX COMMUNICATION SYSTEM (BEAN)

INSPECT FUSE (ECU-IG LH)

INSPECT POWER STEERING ECU ASSEMBLY

CHECK HARNESS AND CONNECTOR (POWER STEERING ECU ASSEMBLY - BODY GROUND)

REPLACE POWER STEERING ECU ASSEMBLY

CHECK P/S WARNING LIGHT

ELECTRONIC POWER STEERING SYSTEM - IG Power Source Circuit


DESCRIPTION

The troubleshooting procedure for a situation in which no DTCs are output but the P/S warning light is always on is specified here. The P/S warning light remains on when there is an open in the IG circuit inputting power source voltage to the power steering ECU assembly.

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.Power Steering.Power Steering System.Electronic Power Steering System Ig Power Source Circuit


INSPECTION PROCEDURE

1.CHECK HARNESS AND CONNECTOR

  1. Check the indication condition of the P/S warning light while by wiggling the power steering ECU assembly connector and wire harness up and down, and right and left.

    OK:
    P/S warning light indication condition does not change.


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


2.INSPECT CAN COMMUNICATION SYSTEM

  1. Using the intelligent tester, check for DTCs and confirm that there are no problems in the CAN communication system.

    OK:
    DTCs are not output.


NG
GO TO CAN COMMUNICATION SYSTEM
OK


3.INSPECT MULTIPLEX COMMUNICATION SYSTEM (BEAN)

  1. Using the intelligent tester, check for DTCs and confirm that there are no problems in the multiplex communication system (BEAN).

    OK:
    DTCs are not output.


NG
GO TO MULTIPLEX COMMUNICATION SYSTEM (BEAN)
OK


4.INSPECT FUSE (ECU-IG LH)

  1. Remove the ECU-IG LH fuse from the cowl side J/B LH.

  1. Check for continuity of the ECU-IG LH fuse.

    OK:
    Continuity


NG
REPLACE FUSE
OK


5.INSPECT POWER STEERING ECU ASSEMBLY

  1. Disconnect the A24 connector from the power steering ECU assembly.



    Lexus Gs430, Gs300. Uzs190 Grs190.Power Steering.Power Steering System.Electronic Power Steering System Ig Power Source Circuit

  1. Measure the voltage according to the value(s) in the table below.

    Voltage:
    Tester connection
    (Symbols)
    		Condition
    		Specified condition
    A24-9 (IG) -A24-5 (PGND)
    		Engine switch on (IG)
    		10 to 14 V


OK
Go to step 7
NG


6.CHECK HARNESS AND CONNECTOR (POWER STEERING ECU ASSEMBLY - BODY GROUND)


    Lexus Gs430, Gs300. Uzs190 Grs190.Power Steering.Power Steering System.Electronic Power Steering System Ig Power Source Circuit

  1. Measure the resistance according to the value(s) in the table below.

    Resistance:
    Tester connection
    (Symbols)
    		Condition
    		Specified condition
    A24-5 (PGND) - Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER STEERING ECU ASSEMBLY - BATTERY)

7.REPLACE POWER STEERING ECU ASSEMBLY
NOTICE:
If replacing the power steering ECU assembly, initialize the rotation angle sensor and calibrate the torque sensor zero point (Click here).

NEXT


8.CHECK P/S WARNING LIGHT

  1. Check the P/S warning light status on the combination meter.

    Standard:
    The P/S warning light is off.


OK
END
NG

REPLACE PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE