Meter Illumination Is Always Dark

METER / GAUGE / DISPLAY: METER / GAUGE SYSTEM: Meter Illumination is Always Dark
- Meter Illumination is Always Dark

DESCRIPTION

In this circuit, the meter CPU receives auto dimmer signals from the main body ECU using the CAN communication system (CAN V1 Bus). When the meter CPU receives an auto dimmer signal, it dims the meter illumination (warning and indicator lights). The main body ECU determines whether it is daytime, twilight, or nighttime based on the waveform transmitted from the automatic light control sensor. If the main body ECU determines that it is daytime, the ECU does not send an auto dimmer signal. Therefore, the meter illumination will not dim even if the driver accidentally turns the light control switch to the tail or head position in daytime.

HINT
When the meter illumination is always dark, there may be a malfunction in the automatic light control sensor, main body ECU, CAN communication system, harness or connector, or combination meter assembly.

WIRING DIAGRAM





INSPECTION PROCEDURE

HINT
* The meter illumination can be customized by pressing the turning the light control rheostat knob in the combination meter assembly.
* If the light control rheostat knob is turned fully clockwise and the light control switch is turned to the tail, head or AUTO position at night, the meter illumination goes off.

PROCEDURE

1. CHECK CAN COMMUNICATION SYSTEM

(a) Check if a CAN communication DTC is output Diagnosis System.

Result





B -- GO TO CAN COMMUNICATION SYSTEM How to Proceed With Troubleshooting
A -- Continue to next step.

2. CONFIRM DTC OUTPUT (LIGHT CONTROL SENSOR CIRCUIT)

(a) Check if DTC B1244 is output Reading and Clearing Diagnostic Trouble Codes.

Result





B -- GO TO LIGHTING SYSTEM Exterior Lighting System
A -- Continue to next step.

3. CHECK OPERATION (ACCESSORY METER ASSEMBLY)

(a) Turn the ignition switch to ON.

(b) Turn the light control switch to the tail, head or AUTO position.

(c) Cover the automatic light control sensor.

(d) Check the accessory meter assembly illumination.

Result





HINT
The accessory meter assembly illumination dims according to the dimmer signal as the combination meter assembly does. Therefore, when only the meter illumination is always dark, there may be a malfunction in the combination meter assembly.

B -- REPLACE COMBINATION METER ASSEMBLY Removal
A -- Continue to next step.

4. CHECK OPERATION (AUTOMATIC LIGHT CONTROL SYSTEM)

(a) Turn the ignition switch to ON.

(b) Turn the light control switch to the AUTO position.

(c) Cover the automatic light control sensor.

(d) Check the taillights and low beam headlights.

OK:

The taillights and low beam headlights come on.

(e) Uncover the automatic light control sensor.

(f) Check the low beam headlights and taillights.

OK:

The low beam headlights and taillights go off.

Result





B -- CHECK LIGHTING SETTING Exterior Lighting System
A -- Continue to next step.

5. REPLACE MAIN BODY ECU

(a) Replace the main body ECU with a new or a normal one Removal.

OK:

The operation of the combination meter assembly returns to normal.

HINT
The meter CPU controls the meter illumination based on an auto dimmer signal from the main body ECU. When the meter illumination is always dark (very dim), it may be due to the main body ECU sending an auto dimmer signal to the meter CPU because of a malfunction in the main body ECU.

NG -- REPLACE COMBINATION METER ASSEMBLY Removal

OK -- END