Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Parking Light/Daytime Running Light Circuit
DESCRIPTION
- When the main body ECU (multiplex network body ECU) receives the light control switch position signal, it sends an illumination request signal to the No. 1 headlight ECU sub-assembly and illuminates the parking lights.
- When the operation conditions of the daytime running lights are met, the main body ECU (multiplex network body ECU) sends an illumination request signal to the No. 1 headlight ECU sub-assembly and illuminates the daytime running lights.
WIRING DIAGRAM
for Multiple Beam Headlight
for Single Beam Headlight
CAUTION / NOTICE / HINT
NOTICE:
-
If the No. 1 headlight ECU sub-assembly LH has been replaced, it is necessary to synchronize the vehicle information and initialize the No. 1 headlight ECU sub-assembly LH.
Click here
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-
If the headlight assembly LH has been replaced, it is necessary to synchronize the vehicle information and initialize the No. 1 headlight ECU sub-assembly LH.*
Click here
- When replacing the No. 1 headlight ECU sub-assembly LH, always replace it with a new one. If a No. 1 headlight ECU sub-assembly LH which was installed to another vehicle is used, the information stored in it will not match the information from the vehicle and a DTC may be stored.
-
When replacing the headlight assembly LH, always replace it with a new one. If a headlight assembly LH which was installed to another vehicle is used, the information stored in it will not match the information from the vehicle and a DTC may be stored.*
- *: for TMMC Made
PROCEDURE
| 1. | CONFIRM MODEL |
(a) Choose the model to be inspected.
| Result | Proceed to |
|---|---|
| for Multiple Beam Headlight | A |
| for Single Beam Headlight | B |
| B | .gif) | GO TO STEP 3 |
|
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| 2. | 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 / AFS / Active Test.
(e) Perform the Active Test according to the display on the Techstream.
Body Electrical > AFS > Active Test| Tester Display | Measurement Item | Control Range | Diagnostic Note |
|---|---|---|---|
| Clearance Light | Parking lights | OFF or ON | - |
| Daytime Running Light | Daytime running lights | OFF or ON | This Active Test can only be performed when the customization item DRL function is set to "ON" using the Techstream. |
| Tester Display |
|---|
| Clearance Light |
| Tester Display |
|---|
| Daytime Running Light |
OK:
Parking lights and daytime running lights illuminate.
| Result | Proceed to |
|---|---|
| OK | A |
| NG (LH side parking light and daytime running light does not illuminate) | B |
| NG (RH side parking light and daytime running light does not illuminate) | C |
| A | | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
| B | | GO TO STEP 4 |
| C | | GO TO STEP 6 |
| 3. | 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 / HL AutoLeveling / Active Test.
(e) Perform the Active Test according to the display on the Techstream.
Body Electrical > HL AutoLeveling > Active Test| Tester Display | Measurement Item | Control Range | Diagnostic Note |
|---|---|---|---|
| Clearance Light | Parking lights | OFF or ON | - |
| Daytime Running Light | Daytime running lights | OFF or ON | This Active Test can only be performed when the customization item DRL function is set to "ON" using the Techstream. |
| Tester Display |
|---|
| Clearance Light |
| Tester Display |
|---|
| Daytime Running Light |
OK:
Parking lights and daytime running lights illuminate.
| Result | Proceed to |
|---|---|
| OK | A |
| NG (LH side parking light and daytime running light does not illuminate) | B |
| NG (RH side parking light and daytime running light does not illuminate) | C |
| A | | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
| C | | GO TO STEP 6 |
|
| 4. | CHECK HEADLIGHT UNIT LH |
(a) Interchange the headlight unit LH with RH and connect the connectors.
Click here
|
| 5. | CHECK OPERATION (PARKING LIGHTS AND DAYTIME RUNNING LIGHTS) |
(a) Check the operation of the parking lights and daytime running lights.
OK:
The parking lights and daytime running lights operate normally.
| Result | Proceed to |
|---|---|
| OK | A |
| NG (for TMC Made) | B |
| NG (for TMMC Made) | C |
| A | | REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH |
| B | | REPLACE HEADLIGHT UNIT LH |
| C | | REPLACE HEADLIGHT ASSEMBLY LH |
| 6. | CHECK HEADLIGHT UNIT RH |
(a) Interchange the headlight unit RH with LH and connect the connectors.
Click here
|
| 7. | CHECK OPERATION (PARKING LIGHTS AND DAYTIME RUNNING LIGHTS) |
(a) Check the operation of the parking lights and daytime running lights.
OK:
The parking lights and daytime running lights operate normally.
| Result | Proceed to |
|---|---|
| OK | A |
| NG (for TMC Made) | B |
| NG (for TMMC Made) | C |
| A | | REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH |
| B | | REPLACE HEADLIGHT UNIT RH |
| C | | REPLACE HEADLIGHT ASSEMBLY RH |
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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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