Lexus IS250 IS220d GSE20 ALE20 - POWER STEERING

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK HARNESS AND CONNECTOR

INSPECT CAN COMMUNICATION SYSTEM

INSPECT MULTIPLEX COMMUNICATION SYSTEM

INSPECT FUSE

INSPECT POWER STEERING ECU ASSEMBLY

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

INSPECT COMBINATION METER ASSEMBLY

ELECTRONIC POWER STEERING SYSTEM - PS Warning Light Remains ON

DESCRIPTION

The power steering ECU is connected to the combination meter via CAN and multiplex communications. If any of the following are detected, the PS warning light remains on.


The power steering ECU connectors are disconnected from the power steering ECU.
There is a malfunction in the power steering ECU internal circuit.
There is an open in the harness between the combination meter and power steering ECU assembly.

WIRING DIAGRAM

Electronic Power Steering System - Ps Warning Light Remains On. POWER STEERING. Lexus IS250 IS220d GSE20 ALE20

INSPECTION PROCEDURE

1.CHECK HARNESS AND CONNECTOR

Check the indication condition of the PS warning light while wiggling the power steering ECU assembly connector and wire harness up and down, and right and left.

  • OK:
  • PS warning light indication condition does not change.
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
2.INSPECT CAN COMMUNICATION SYSTEM

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

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
OK
4.INSPECT FUSE

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

Check for continuity of the ECU-IG LH fuse.

  • OK:
  • Below 1 Ω
NG
REPLACE FUSE
OK
5.INSPECT POWER STEERING ECU ASSEMBLY
Electronic Power Steering System - Ps Warning Light Remains On. POWER STEERING. Lexus IS250 IS220d GSE20 ALE20

Disconnect the A31 connector from the power steering ECU assembly.

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

  • Standard voltage:
  • Tester ConnectionConditionSpecified Condition
    A31-9 (IG) - Body groundEngine switch on (IG)10 to 14 V
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
6.CHECK HARNESS AND CONNECTOR (POWER STEERING ECU ASSEMBLY - BODY GROUND)
Electronic Power Steering System - Ps Warning Light Remains On. POWER STEERING. Lexus IS250 IS220d GSE20 ALE20

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

  • Standard resistance:
  • Tester ConnectionConditionSpecified Condition
    A31-5 (PGND) - Body groundEngine switch on (IG)Below 1 Ω
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
7.INSPECT COMBINATION METER ASSEMBLY

Connect the intelligent tester to the DLC3.

Turn the engine switch on (IG).

Perform the Active Test according to the display on the tester.

Combination Meter:
ItemTest DetailsDiagnostic Note
Indicat EPSPS indicator light OFF/ON-
  • OK:
  • PS indicator light comes on.
  • NOTICE:
  • If replacing the power steering ECU assembly, initialize the rotation angle sensor value and calibrate the torque sensor zero point .
NG
REPLACE COMBINATION METER ASSEMBLY
OK
REPLACE POWER STEERING ECU ASSEMBLY
LEXUS IS250, IS220d / GSE20 ALE20
POWER STEERING
Lexus IS250 IS220d GSE20 ALE20
ELECTRONIC POWER STEERING SYSTEM