Lexus NX: Daytime Running Light Relay Circuit
DESCRIPTION
The illumination of the daytime running light (clearance light assembly) or clearance light is controlled by the headlight light control ECU sub-assembly.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
PROCEDURE
| 1. | PERFORM ACTIVE TEST USING TECHSTREAM (DAYTIME RUNNING LIGHT) |
(a) Using the Techstream, perform the Active Test.
Click here .gif)
| Tester Display | Measurement Item | Control Range | Diagnostic Note |
|---|---|---|---|
| Daytime Running Light | Illuminates daytime running lights | ON or OFF | - |
| Tester Display |
|---|
| Daytime Running Light |
| Result | Proceed to |
|---|---|
| The Active Test is performed normally | A |
| The Active Test is not performed normally for the right side light only | B |
| The Active Test is not performed normally for the left side light only | C |
| A | .gif) | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
| C | | GO TO STEP 5 |
|
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| 2. | INSPECT NO. 1 DAYTIME RUNNING LIGHT RELAY (DRL RH) |
(a) Remove the No. 1 daytime running light relay from the No. 2 engine room relay block.
(b) Inspect the No. 1 daytime running light relay.
Click here
| NG | | REPLACE NO. 1 DAYTIME RUNNING LIGHT RELAY (DRL RH) |
|
| 3. | CHECK HARNESS AND CONNECTOR (NO. 1 DAYTIME RUNNING LIGHT RELAY [DRL RH] - BATTERY) |
(a) Remove the No. 1 daytime running light relay from the No. 2 engine room relay block.
| (b) Measure the voltage according to the value(s) in the table below. Standard Voltage:
|
|
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 4. | CHECK HARNESS AND CONNECTOR (NO. 1 DAYTIME RUNNING LIGHT RELAY [DRL RH] - MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU]) |
(a) Remove the No. 1 daytime running light relay from the No. 2 engine room relay block.
(b) Remove the instrument panel junction block assembly.
(c) Disconnect the I47 instrument panel junction block assembly connector.
(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| Relay terminal 2 - I47-22 (DRL) | Always | Below 1 Ω |
| Relay terminal 2 or I47-22 (DRL) - Body ground | Always | 10 kΩ or higher |
| OK | | REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
| 5. | INSPECT NO. 2 DAYTIME RUNNING LIGHT RELAY (DRL LH) |
(a) Remove the No. 2 daytime running light relay from the No. 2 engine room relay block.
(b) Inspect the No. 1 daytime running light relay.
Click here
| NG | | REPLACE NO. 2 DAYTIME RUNNING LIGHT RELAY (DRL LH) |
|
| 6. | CHECK HARNESS AND CONNECTOR (NO. 2 DAYTIME RUNNING LIGHT RELAY [DRL LH] - BATTERY) |
(a) Remove the No. 2 daytime running light relay from the No. 2 engine room relay block.
| (b) Measure the voltage according to the value(s) in the table below. Standard Voltage:
|
|
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 7. | CHECK HARNESS AND CONNECTOR (NO. 2 DAYTIME RUNNING LIGHT RELAY [DRL LH] - MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU]) |
(a) Remove the No. 2 daytime running light relay from the No. 2 engine room relay block.
(b) Remove the instrument panel junction block assembly.
(c) Disconnect the 4B instrument panel junction block assembly connector.
(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| Relay terminal 2 - 4B-51 | Always | Below 1 Ω |
| Relay terminal 2 or 4B-51 - Body ground | Always | 10 kΩ or higher |
| OK | | REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
|
| 8. | INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY |
(a) Remove the driver side junction block assembly.
Click here
| (b) Remove the main body ECU from the driver side junction block assembly. Click here |
|
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A-25 (DRLE) - 4B-51 | Always | Below 1 Ω |
| OK | | REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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