Toyota Tacoma (2015-2018) Service Manual: Meter Illumination is Always Dark
DESCRIPTION
In this circuit, the combination meter assembly receives auto dimmer signals from the main body ECU (multiplex network 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 (multiplex network 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 (multiplex network 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 (multiplex network body ECU), CAN communication system, harness or connector, or combination meter assembly.
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 (See page
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)*1
- *1: w/ Smart Key System
WIRING DIAGRAM
CAUTION / NOTICE / HINT
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 (See page
).
|
Result |
Proceed to |
|---|---|
|
CAN communication DTC is not output |
A |
|
CAN communication DTC is output |
B |
| B | .gif) |
GO TO CAN COMMUNICATION SYSTEM |
|
.gif)
|
2. |
CONFIRM DTC OUTPUT (LIGHT CONTROL SENSOR CIRCUIT) |
(a) Check if DTC B1244 is output (See page
).
|
Result |
Proceed to |
|---|---|
|
B1244 is not output |
A |
|
B1244 is output |
B |
| B | |
GO TO LIGHTING SYSTEM |
|
|
3. |
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|
Result |
Proceed to |
|---|---|
|
Automatic light control system operates normally |
A |
|
Automatic light control system does not operate normally |
B |
| B | |
CHECK LIGHTING SETTING |
|
|
4. |
REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
(a) Replace the main body ECU (multiplex network body ECU) 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 (multiplex network body ECU). When the meter illumination is always dark (very dim), it may be due to the main body ECU (multiplex network body ECU) sending an auto dimmer signal to the meter CPU because of a malfunction in the main body ECU (multiplex network body ECU).
| OK | |
END (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) WAS DEFECTIVE) |
| NG | |
REPLACE COMBINATION METER ASSEMBLY |
Fuel Receiver Gauge Malfunction
DESCRIPTION
The meter CPU uses the fuel sender gauge assembly to determine the level of the
fuel in the fuel tank. The resistance of the fuel sender gauge will vary between
approximately 13.5 Ω ...
Meter Illumination does not Dim at Night
DESCRIPTION
In this circuit, the combination meter assembly auto dimmer signals from the
main body ECU using the CAN communication system (CAN V1 Bus). When the combination
meter assembly an auto ...
Other materials:
Freeze Frame Data
FREEZE FRAME DATA
CHECK FREEZE FRAME DATA
HINT:
The ECU records vehicle and driving condition information as freeze frame data
the moment a DTC is stored.
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: P ...
Data List / Active Test
DATA LIST / ACTIVE TEST
HINT:
By accessing the Data List displayed on the Techstream, you can perform such
functions as reading the values of switches and sensors without removing any parts.
Reading the Data List is the first step of troubleshooting and is one method to
shorten labor time.
...
If a warning light turns on or a warning buzzer sounds
Calmly perform the following actions if any of the warning lights turn on
or flash. If a light turns on or flashes, but then turns off, this does not necessarily
indicate a malfunction in the system.
Stop the vehicle immediately. Continuing to drive the vehicle may be dangerous.
The following ...
