Meter Illumination Does Not Dim At Night

METER / GAUGE / DISPLAY: METER / GAUGE SYSTEM: Meter Illumination does not Dim at Night
- Meter Illumination does not Dim at Night

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 nighttime and the light control switch is in the tail, head, or AUTO, the ECU sends an auto dimmer signal. According to the signal, the combination meter assembly dims the meter illumination.

HINT
When the meter illumination does not dim at night, 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

* Refer to Meter Illumination is Always Dark Meter Illumination Is Always Dark.

INSPECTION PROCEDURE

HINT
* The automatic light control sensor sensitiveness can be customized Exterior Lighting System.
* Setting the meter illumination to maximum brightness prevents the meter illumination from dimming when the light control switch is changed to the tail, head or AUTO position at night. Therefore, check the meter illumination setting before proceeding to the following steps.

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 light control switch.

(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 does not dim at night, replace 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 that the taillights and low beam headlights.

OK:

The taillights and low beam headlights come on.

(e) Uncover the automatic light control sensor.

(f) Check that 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. If the meter does not dim when the light control switch is in the tail, head, or AUTO position at night, it may be for either of 2 reasons. The first reason is that the main body ECU does not send an auto dimmer signal. The second is that the meter CPU does not dim the meter illumination even though the meter CPU receives an auto dimmer signal.

NG -- REPLACE COMBINATION METER ASSEMBLY Removal

OK -- END