Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual: MIL Circuit

DESCRIPTION

The Malfunction Indicator Lamp (MIL) is used to indicate vehicle malfunctions detected by the ECM.

The MIL operation can be checked visually. When the engine switch is first turned on (IG), the MIL should be illuminated and should then turn off after the engine is started. If the MIL remains illuminated or is not illuminated, conduct the following troubleshooting procedure using the Techstream.

WIRING DIAGRAM

PROCEDURE

1.

CHECK THAT MIL IS ILLUMINATED

(a) Perform troubleshooting in accordance with the table below.

MIL

Condition

Proceed to

Illuminates → Turns off

Engine switch on (IG) → engine is started

A

Other than above

-

B

A

CHECK FOR INTERMITTENT PROBLEMS

B

2.

CHECK COMMUNICATION BETWEEN TECHSTREAM AND ECM

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Check the communication between the Techstream and ECM.

HINT:

It can be checked using the "Engine" item of the Data List.

Result

Proceed to

Communication is possible

A

Communication is not possible

B

B

GO TO VC OUTPUT CIRCUIT

A

3.

CHECK WHETHER DTC OUTPUT RECURS

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Enter the following menus: System Select / Health Check.

(e) Check if any DTCs have been detected. Note down any DTCs.

Result

Proceed to

DTCs are not output

A

Any DTCs is output

B

HINT:

Check for detected DTCs output from other ECUs which relate to the MIL.

B

REPAIR CIRCUIT INDICATED BY OUTPUT

A

4.

PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Combination Meter / Active Test / Check Engine Indicator.

Body Electrical > Combination Meter > Active Test

Tester Display

Check Engine Indicator

(e) Check the status of the MIL while performing the Active Test.

Result

Proceed to

Changes

A

Does not change

B

A

REPLACE ECM

B

REPLACE COMBINATION METER ASSEMBLY

    Brake Override System
    DESCRIPTION When the vehicle is being driven, depressing the accelerator pedal sensor assembly and brake pedal will activate the brake override system to restrict engine output. The conditions for act ...

    Ignition Circuit
    DESCRIPTION A direct ignition system is used on this vehicle. The direct ignition system is a 1 cylinder ignition system which ignites one cylinder with one ignition coil. In the 1 cylinder ignition s ...

    Other materials:

    Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual > Airbag System: Vehicle Control History
    VEHICLE CONTROL HISTORY Function Overview (a) The vehicle control history is a function that records control data (record data) when triggered by specific vehicle behavior or user input. Checking the vehicle control history may provide, quantitative diagnostic information that can be used as a refer ...

    Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual > Power Door Lock Control System: Dtc Check / Clear
    DTC CHECK / CLEAR CHECK DTC (a) Connect the Techstream to the DLC3. (b) Turn the engine switch on (IG). (c) Turn the Techstream on. (d) Enter the following menus: Body Electrical / Main Body / Trouble Codes. Body Electrical > Main Body > Trouble Codes (e) Check for DTCs. Click here CLEAR DT ...

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

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

    © 2026 Copyright www.lexusrx.net
    0.0087