Lexus NX: Taillight Relay Circuit
DESCRIPTION
Illumination of the taillights and license plate light is controlled by the main body ECU (multiplex network body ECU).
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
- Inspect the fuses for circuits related to this system before performing the following procedure.
- Recognition code registration is necessary when replacing the main body ECU (multiplex network body ECU).
-
If the main body ECU (multiplex network body ECU) is replaced, refer to Registration.
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PROCEDURE
| 1. | PERFORM ACTIVE TEST USING TECHSTREAM (TAILLIGHT RELAY) |
(a) Using the Techstream, perform the Active Test.
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| Tester Display | Measurement Item | Control Range | Diagnostic Note |
|---|---|---|---|
| Taillight Relay | Taillight relay | ON or OFF | - |
| Tester Display |
|---|
| Taillight Relay |
| Result | Proceed to |
|---|---|
| Taillights, license lights and side marker lights come on | A |
| Taillights, license lights and side marker lights do not come on | B |
| A | .gif) | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
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| 2. | CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - BATTERY) |
(a) Disconnect the instrument panel junction block assembly connector.
| (b) Measure the voltage according to the value(s) in the table below. Standard Voltage:
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| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 3. | INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY |
(a) Remove the instrument panel junction block assembly.
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(b) Remove the instrument panel junction block assembly.
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(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 4A-37 - Battery negative (-) terminal | Battery voltage applied between terminals 4F-1 and A-14 (TRLY) | 11 to 14 V |
| Battery voltage not applied between terminals 4F-1 and A-14 (TRLY) | Below 1 V | |
| 4A-38 - Battery negative (-) terminal | Battery voltage applied between terminals 4F-1 and A-14 (TRLY) | 11 to 14 V |
| Battery voltage not applied between terminals 4F-1 and A-14 (TRLY) | Below 1 V | |
| 4B-24 - Battery negative (-) terminal | Battery voltage applied between terminals 4F-1 and A-14 (TRLY) | 11 to 14 V |
| Battery voltage not applied between terminals 4F-1 and A-14 (TRLY) | Below 1 V | |
| 4B-25 - Battery negative (-) terminal | Battery voltage applied between terminals 4F-1 and A-14 (TRLY) | 11 to 14 V |
| Battery voltage not applied between terminals 4F-1 and A-14 (TRLY) | Below 1 V | |
| 4B-25 - Battery negative (-) terminal | Battery voltage applied between terminals 4F-1 and A-14 (TRLY) | 11 to 14 V |
| Battery voltage not applied between terminals 4F-1 and A-14 (TRLY) | Below 1 V |
| OK | | REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
| NG | | REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY |
READ NEXT:
Power Source Circuit
DESCRIPTION The main body ECU (multiplex network body ECU) receives IG signals and supplies power to the headlight ECU sub-assembly via the H-LP relay. WIRING DIAGRAM CAUTION / NOTICE / HINT NOTICE:
Cornering Light Circuit
DESCRIPTION The illumination of the fog light assembly (cornering light) is controlled by the headlight ECU sub-assembly. WIRING DIAGRAM CAUTION / NOTICE / HINT NOTICE:
The light system (for Tripl
SEE MORE:
Precaution
PRECAUTION PRECAUTIONS FOR FRONT RADAR SENSOR SYSTEM (a) The millimeter wave radar sensor assembly may not be able to reliably detect the following objects:
Pylons made from plastic, etc., glass surfaces such as the entrance to a convenience store, low to the ground objects such as curbs, etc.
How To Proceed With Troubleshooting
CAUTION / NOTICE / HINT HINT:
Use the following procedure to troubleshoot the lighting system.
*: Use the Techstream.
PROCEDURE 1. VEHICLE BROUGHT TO WORKSHOP
NEXT 2. INSPECT AUXILIARY BATTERY VOLTAGE (a) Measure the auxiliary battery voltage with the power
