Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual: IG Power Supply Voltage (C1551)

DESCRIPTION

The power steering ECU assembly distinguishes the engine switch status as on (IG) or off through the IG power source circuit.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Warning Indicate

Return-to-normal Condition

Note

C1551

IG Power Supply Voltage

Open or short in IG power source circuit with engine switch on (IG)

  • ECU-IG NO. 7 (w/o stop and start system)
  • IG power source circuit
  • Power steering ECU assembly

EPS warning light: Comes on

The ECU judges the system has returned to normal or the power switch is turned on (IG) again

-

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • If the power steering ECU assembly has been replaced, perform assist map writing and torque sensor zero point calibration.

    Click here

  • Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (BATTERY - POWER STEERING ECU ASSEMBLY)

(a) Disconnect the J5 and J4 power steering ECU assembly connectors.

*a

Front view of wire harness connector

(to Power Steering ECU Assembly)

-

-

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

J4-1 (IG) - Body ground

Engine switch on (IG)

8 to 16 V

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

J5-2 (PGND) - Body ground

Always

Below 1 Ω

OK

REPLACE POWER STEERING ECU ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

    Vehicle Speed Signal (C1541)
    DESCRIPTION The power steering ECU assembly receives vehicle speed signals from the skid control ECU (brake actuator assembly) via CAN communication. The ECU provides appropriate assist force in accor ...

    PIG Power Supply Voltage (C1552,C1554)
    DESCRIPTION If a problem occurs in the system, the power source relay circuit and the motor relay circuit are shut off to stop power assist. The ECU must be replaced when there is a problem with the r ...

    Other materials:

    Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual > Combination Meter: Reassembly
    REASSEMBLY PROCEDURE 1. INSTALL COMBINATION METER GLASS (for Optitron Meter Type) (a) Engage the 8 claws to install the combination meter glass. 2. INSTALL COMBINATION METER GLASS (for TFT Meter Type) (a) Engage the 9 claws to install the combination meter glass. ...

    Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual > Intelligent Clearance Sonar System: Vehicle Information Unmatched (C168D)
    DESCRIPTION If the vehicle information stored in the main body ECU (multiplex network body ECU) which is sent via CAN communication during the clearance warning ECU assembly self-diagnosis does not match that of clearance warning ECU assembly, DTC C168D is stored. DTC No. Detection Item DTC D ...

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual

    © 2026 Copyright www.lexusrx.net
    0.0101