Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Low Beam Headlight Circuit
DESCRIPTION
The main body ECU (multiplex network body ECU) controls the low beam headlights.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
- Inspect the fuses for circuits related to this system before performing the following procedure.
-
Before replacing the main body ECU (multiplex network body ECU), refer to Registration.
Click here
.gif)
PROCEDURE
| 1. | 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 / Main Body / Active Test.
(e) Perform the Active Test according to the display on the Techstream.
Body Electrical > Main Body > Active Test| Tester Display | Measurement Item | Control Range | Diagnostic Note |
|---|---|---|---|
| Headlight Relay | Low beam headlights | OFF/ON | - |
| Tester Display |
|---|
| Headlight Relay |
OK:
Low beam headlights illuminate.
| OK | .gif) | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
|
.gif)
| 2. | INSPECT SEMICONDUCTOR POWER INTEGRATION ECU |
(a) Remove the semiconductor power integration ECU from the engine room relay block and junction block assembly.
Click here
(b) Inspect the semiconductor power integration ECU.
Click here
OK:
Semiconductor power integration ECU is normal.
| NG | | REPLACE SEMICONDUCTOR POWER INTEGRATION ECU |
|
| 3. | CHECK HARNESS AND CONNECTOR (POWER SOURCE - SEMICONDUCTOR POWER INTEGRATION ECU) |
(a) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| B-1 (BATT) - Body ground | Always | 11 to 14 V |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 4. | CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY) |
(a) Disconnect the 2C instrument panel junction block assembly connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 1D-8 - 2C-31 | Always | Below 1 Ω |
| 1D-8 or 2C-31 - Body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 5. | INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY |
| *a | Component without harness connected (Instrument Panel Junction Block Assembly) | - | - |
(a) Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.
Click here
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 2C-31 - MB-15 (HRLY) | Always | Below 1 Ω |
| OK | | REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
| NG | | REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY |
Taillight Relay Circuit
DESCRIPTION The main body ECU (multiplex network body ECU) controls the operation of the TAIL relay. WIRING DIAGRAM CAUTION / NOTICE / HINT NOTICE:
Inspect the fuses for circuits related to this s ...
High Beam Headlight Circuit
DESCRIPTION The main body ECU (multiplex network body ECU) controls the high beam headlights. WIRING DIAGRAM CAUTION / NOTICE / HINT NOTICE:
Inspect the fuses for circuits related to this system b ...
Other materials:
Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Steering Heater Switch: Removal
REMOVAL PROCEDURE 1. REMOVE INSTRUMENT PANEL GARNISH LH Click here 2. REMOVE FRONT DOOR SCUFF PLATE LH w/ Rear No. 2 Seat: Click here w/o Rear No. 2 Seat: Click here 3. REMOVE COWL SIDE TRIM BOARD LH Click here 4. REMOVE NO. 1 INSTRUMENT PANEL UNDER COVER SUB-ASSEMBLY Click here 5. DI ...
Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Stop Light Switch: 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 stop light switch removal/installation are shown below. Necessary Procedures After Parts Removed/Install ...
Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual
- For your information
- Pictorial index
- For safety and security
- Instrument cluster
- Operation of each component
- Driving
- Lexus Display Audio system
- Interior features
- Maintenance and care
- When trouble arises
- Vehicle specifications
- For owners
Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual
0.0192