Lexus NX: Problem Symptoms Table
PROBLEM SYMPTOMS TABLE
NOTICE:
- 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.
- When replacing the combination meter assembly, always replace it with a new one. If a combination meter assembly 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.
HINT:
- Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
- Inspect the fuses related to this system before inspecting the suspected areas below.
| Symptom | Suspected Area | Link |
|---|---|---|
| One low beam headlight does not illuminate. | Harness or connector | - |
| Headlight assembly | | |
| Both left and right low beam headlights do not illuminate. | Headlight relay (H-LP [LO]) | |
| Headlight dimmer switch circuit | | |
| Low beam headlight circuit | | |
| Main body ECU (Multiplex network body ECU) | | |
| One high beam headlight does not illuminate. | Harness or connector | - |
| Headlight assembly | | |
| Both left and right high beam headlights do not illuminate. | Headlight dimmer relay (H-LP LH/DIMMER [HI]) | |
| Headlight dimmer switch circuit | | |
| High beam headlight circuit | | |
| Main body ECU (Multiplex network body ECU) | | |
| High beam flash function does not operate (high beam headlights are normal). | Headlight dimmer switch circuit | |
| Main body ECU (Multiplex network body ECU) | | |
| One front side marker light does not illuminate. | Headlight assembly | |
| Harness or connector | - | |
| Both left and right side marker lights do not illuminate. | Harness or connector | - |
| Instrument panel junction block assembly | |
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| Symptom | Suspected Area | Link |
|---|---|---|
| One side marker light does not illuminate. | Headlight assembly | |
| Harness or connector | - |
| Symptom | Suspected Area | Link |
|---|---|---|
| One clearance light on right side does not illuminate. | Clearance light assembly | |
| Harness or connector | - |
| Symptom | Suspected Area | Link |
|---|---|---|
| Both left and right daytime running lights do not illuminate. | Headlight dimmer switch circuit | |
| Main body ECU (Multiplex network body ECU) | | |
| Harness or connector | - | |
| One daytime running light does not illuminate. | Daytime running light relay circuit | |
| Harness or connector | - | |
| One clearance light and daytime running light does not illuminate. | Daytime running light relay circuit | |
| Harness or connector | - |
| Symptom | Suspected Area | Link |
|---|---|---|
| Both front fog lights do not illuminate (taillight is normal). | Headlight dimmer switch circuit | |
| Front fog light circuit | | |
| Main body ECU (Multiplex network body ECU) | |
| Symptom | Suspected Area | Link |
|---|---|---|
| License plate light does not illuminate. | Harness or connector | - |
| License plate light assembly LH | | |
| License plate light assembly RH | |
| Symptom | Suspected Area | Link |
|---|---|---|
| Taillight (rear combination light assembly) does not illuminate. | Rear combination light socket and wire sub-assembly | |
| Rear combination light assembly | | |
| Harness or connector | - | |
| Instrument panel junction block assembly | | |
| Taillight (rear light assembly) does not illuminate. | Rear light assembly | |
| Harness or connector | - | |
| Instrument panel junction block assembly | | |
| All of the taillights do not illuminate | Headlight dimmer switch circuit | |
| Taillight relay circuit | | |
| Main body ECU (Multiplex network body ECU) | |
| Symptom | Suspected Area | Link |
|---|---|---|
| Stop light (rear combination light assembly) on one side does not illuminate. | Rear combination light socket and wire sub-assembly | |
| Rear combination light assembly | | |
| Harness or connector | - | |
| Stop light (rear light assembly) on one side does not illuminate. | Rear light assembly | |
| Harness or connector | - | |
| Center stop light does not illuminate. | Center stop light assembly | |
| Harness or connector | - | |
| All of the stop lights do not operate. | Harness or connector | - |
| Stop light switch assembly | | |
| Stop light control ECU assembly | |
| Symptom | Suspected Area | Link |
|---|---|---|
| All of the back-up lights do not operate. | Harness or connector | - |
| Instrument panel junction block assembly [BKUP LP relay] | | |
| Hybrid vehicle control ECU | | |
| Back-up light on one side does not illuminate. | Rear light assembly | |
| Harness or connector | - |
| Symptom | Suspected Area | Link |
|---|---|---|
| No turn signal lights operate (hazard warning lights are normal). | Turn signal switch circuit | |
| Combination meter assembly | | |
| One of the turn signal lights does not operate. | Meter/gauge system | |
| Symptom | Suspected Area | Link |
|---|---|---|
| Hazard warning lights do not operate (turn signal lights are normal). | Harness or connector | - |
| Hazard warning switch circuit | | |
| Combination meter assembly | |
| Symptom | Suspected Area | Link |
|---|---|---|
| Automatic light control system does not operate. | Headlight dimmer switch circuit | |
| Main body ECU (Multiplex network body ECU) | |
| Symptom | Suspected Area | Link |
|---|---|---|
| Light auto turn-off system does not operate. | Headlight dimmer switch circuit | |
| Door courtesy switch circuit | | |
| IG signal circuit | | |
| Main body ECU (Multiplex network body ECU) | |
| Symptom | Suspected Area | Link |
|---|---|---|
| Welcome light illumination control does not operate. | Wireless door lock control system | |
| Headlight dimmer switch circuit | | |
| Main body ECU (Multiplex network body ECU) | |
| Symptom | Suspected Area | Link |
|---|---|---|
| Lexus Enform Remote does not operate (lighting system is normal). | Telematics system | |
READ NEXT:
Terminals Of Ecu
TERMINALS OF ECU CHECK INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY, MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) (a) Remove the main body ECU (multiplex network body ECU) from the instrument panel junction
Dtc Check / Clear
DTC CHECK / CLEAR CHECK FOR DTC (a) Connect the Techstream to the DLC3. (b) Turn the power switch on (IG). (c) Turn the Techstream on. (d) Enter the following menus: Body Electrical / Main body / Trou
Freeze Frame Data
FREEZE FRAME DATA FREEZE FRAME DATA (a) Whenever a lighting system DTC is stored, the forward recognition camera stores the current vehicle state as freeze frame data. CHECK FREEZE FRAME DATA (a) Conn
SEE MORE:
Diagnosis System
DIAGNOSIS SYSTEM DIAGNOSIS MODE FUNCTION (a) w/ Lane Centering Function: When a malfunction occurs in the lane tracing assist system system, the LTA indicator light illuminates yellow and a message is displayed on the multi-information display. Warning Message Details DTC/RoB LTA Indicator
Panel Switches do not Function
CAUTION / NOTICE / HINT NOTICE: When replacing the radio receiver assembly, always replace it with a new one. If a radio receiver assembly which was installed to another vehicle is used, the following may occur:
A communication malfunction DTC may be stored.
The radio receiver assembly may not
