Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: On-vehicle Inspection

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Power Source & Network / Power Distribution / Integration Relay / On-vehicle Inspection

ON-VEHICLE INSPECTION

PROCEDURE

1. INSPECT SEMICONDUCTOR POWER INTEGRATION ECU (SIGNAL READING CHECK)

NOTICE:

Both present and history signal readings will be cleared if the semiconductor power integration ECU is removed. Make sure not to remove it before inspection.

HINT:

The signal readings of the semiconductor power integration ECU can be checked by inspecting the voltage at the diagnosis terminal.

(a) Signal reading check

(1) Turn the engine switch on (IG).

(2) Connect the positive (+) terminal of a voltmeter to the semiconductor power integration ECU and the negative (-) terminal to the body ground.

*a

Component with harness connected

(Semiconductor Pwr Integration ECU)

*b

Diagnosis Terminal

(3) Using the illustration below as a reference, determine whether any channels are malfunctioning based on the observed signal reading.

HINT:

  • The present signal reading and history signal reading will be displayed alternately after the engine switch is turned on (IG). By measuring the duration of each header, the present signal reading and history signal reading can be recognized.
  • A unit malfunction indicates an internal malfunction of the semiconductor power integration ECU. If a malfunction is detected for any channel from channel 0 to 7, an electrical load connected to the semiconductor power integration ECU may be malfunctioning or there may be a short in the semiconductor power integration ECU circuit or in the wire harness.
  • The present signal reading will be stored as a history signal reading when electrical loads are operated after a malfunctioning part returns to normal.
  • Both present and history signal readings can be cleared by disconnecting the cable from the negative (-) battery terminal.
  • Depending on the specification, different electrical loads connected to channels 0 to 7 are provided. Refer to the table below:

    Channel

    Connected Electrical Load

    ch0

    Cooler compressor assembly (Magnetic clutch assembly)

    ch1

    Rear window defogger wire

    ch2

    Windshield deicer wire*1

    ch3

    Front fog lights

    ch4

    Daytime running lights*2

    ch5

    Stop lights

    ch6

    High beam headlight RH*2

    ch7

    High beam headlight LH*2
  • *1: w/ Windshield Deicer System
  • *2: w/o Headlight Beam Level Control System

2. INSPECT SEMICONDUCTOR POWER INTEGRATION ECU (RESULTS OF SIGNAL READING CHECK)

(a) Results of signal reading check

(1) Depending on the signal reading, perform troubleshooting according to the table below.

Output Signal Reading

Repair Method

Normal

Continue troubleshooting for each system.

The unit is malfunctioning

Replace the semiconductor power integration ECU.

A malfunction in a channel (ch0 to ch7)
  1. Check for a short in the wire harnesses between the semiconductor power integration ECU and each electrical load.
  2. Inspect each of the electrical loads.
  3. Replace the semiconductor power integration ECU.

HINT:

Make sure to clear the signal readings by disconnecting the cable from the negative (-) battery terminal after replacement or repair of the malfunctioning part.

(2) If no signal readings are output, perform troubleshooting according to the following troubleshooting procedure.

*a

Component without semiconductor power integration ECU

(No. 1 Engine Room Relay Block)

-

-
  1. Remove the semiconductor power integration ECU.

    Click here

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

    Standard Voltage:

    Tester Connection

    Condition

    Specified Condition

    1D-11 - Body ground

    Engine switch on (IG)

    11 to 14 V

    If the result is not as specified, repair or replace the wire harness or connector.

    Components
    COMPONENTS ILLUSTRATION *1 BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY *2 NO. 1 RELAY BLOCK COVER *3 RESERVOIR BRACKET *4 SEMICONDUCTOR POWER INTEGRATION ECU N*m (kgf*cm, ft.*l ...

    Removal
    REMOVAL CAUTION / NOTICE / HINT The necessary procedures (adjustment, calibration, initialization, or registration) that must be performed after parts are removed and installed, or replaced during int ...

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

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

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