Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual: High Beam Headlight Circuit
DESCRIPTION
The main body ECU (multiplex network body ECU) controls the high beam headlights.
WIRING DIAGRAM
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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
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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 |
|---|---|---|---|
| Head Light Hi | High beam headlights | OFF/ON | - |
| Tester Display |
|---|
| Head Light Hi |
OK:
High beam headlights illuminate.
| OK | .gif) | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
|
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| 2. | CHECK SEMICONDUCTOR POWER INTEGRATION ECU |
(a) Using a voltmeter, check the signal reading of the semiconductor power integration ECU.
Click here
OK:
Output signal reading is normal.
| NG | | INSPECT SEMICONDUCTOR POWER INTEGRATION ECU (RESULTS OF SIGNAL READING CHECK) |
|
| 3. | CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU POWER SOURCE AND BODY GROUND) |
| *a | Component without semiconductor power integration ECU connected (Engine Room Relay Block and Junction Block Assembly) | - | - |
(a) Remove the semiconductor power integration ECU from the engine room relay block and junction block assembly.
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(b) 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 |
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 1D-14 (GND1) - Body ground | Always | Below 1 Ω |
| 1G-5 (GND2) - Body ground | Always | Below 1 Ω |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 4. | CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)) |
(a) Disconnect the J8 main body ECU (multiplex network body ECU) connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 1D-2 (-S) - J8-1 (DIM) | Always | Below 1 Ω |
| 1D-2 (-S) or J8 -1 (DIM) - Body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 5. | REPLACE SEMICONDUCTOR POWER INTEGRATION ECU |
(a) Replace the semiconductor power integration ECU with a new one.
Click here
|
| 6. | CHECK OPERATION (HIGH BEAM HEADLIGHTS) |
(a) Check the operation of the high beam headlights.
OK:
High beam headlights operate normally.
| OK | | END (SEMICONDUCTOR POWER INTEGRATION ECU WAS DEFECTIVE) |
| NG | | REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
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 be ...
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Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual
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Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual
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