Toyota Venza: Meter Illumination is Always Dark

Toyota Venza Service Manual / Meter / Gauge / Display / Meter / Gauge System / Meter Illumination is Always Dark

DESCRIPTION

In this circuit, the meter CPU receives auto dimmer signals from the main body ECU (driver side junction block assembly) using the CAN communication system (CAN No. 1 Bus). When the meter CPU receives an auto dimmer signal, it dims the meter illumination (warning and indicator lights). The main body ECU (driver side junction block assembly) determines whether it is daytime, twilight, or nighttime based on the waveform transmitted from the automatic light control sensor. If the main body ECU (driver side junction block assembly) 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 (driver side junction block assembly), CAN communication system, harness or connector, or combination meter assembly.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

HINT:

The meter illumination can be customized by 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 (See page ).

Result	Proceed to
CAN communication DTC is not output.	A
CAN communication DTC is output.	B

GO TO CAN COMMUNICATION SYSTEM

2.	CHECK DTC (LIGHT SENSOR CIRCUIT)

(a) Check if DTC B1244 is output (See page
).

Result	Proceed to
B1244 is not output.	A
B1244 is output.	B

GO TO LIGHTING SYSTEM

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.

(d) Check the accessory meter assembly illumination.

Result	Proceed to
Accessory meter assembly illumination does not operate normally.	A
Accessory meter assembly illumination operates normally.	B

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.

REPLACE COMBINATION METER ASSEMBLY

4.	CHECK OPERATION (AUTOMATIC LIGHT CONTROL SYSTEM)

(a) Turn the ignition switch to ON.

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

(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	Proceed to
Automatic light control system operates normally.	A
Automatic light control system does not operate normally.	B

CHECK LIGHTING SETTING

5.	REPLACE MAIN BODY ECU (DRIVER SIDE JUNCTION BLOCK ASSEMBLY)

(a) Replace the main body ECU (driver side junction block assembly) with a new or a normal one (See page ).

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 (driver side junction block assembly). When the meter illumination is always dark (very dim), it may be due to the main body ECU (driver side junction block assembly) sending an auto dimmer signal to the meter CPU because of a malfunction in the main body ECU (driver side junction block assembly).

END

REPLACE COMBINATION METER ASSEMBLY

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