Toyota Tacoma (2015-2018) Service Manual: Low Beam Headlight Circuit
DESCRIPTION
The main body ECU (multiplex network body ECU) controls the low beam headlights.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
- Inspect the fuses for circuits related to this system before performing the following inspection procedure.
- If the main body ECU (multiplex network body ECU) is replaced, refer
to Registration (See page
.gif)
).*1
- *1: w/ Smart Key System
PROCEDURE
|
1. |
PERFORM ACTIVE TEST USING TECHSTREAM (HEADLIGHT RELAY) |
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / Main Body / Active Test.
(e) Perform the Active Test according to the display on the Techstream.
Main Body|
Tester Display |
Test Part |
Control Range |
Diagnostic Note |
|---|---|---|---|
|
Headlight Relay |
Headlight relays |
ON/OFF |
- |
OK:
Headlight relays operate. (Low beam headlights illuminate.)
| OK | .gif) |
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
|
.gif)
|
2. |
INSPECT H-LP LO RELAY |
|
(a) Remove the H-LP LO relay from the engine room relay block. |
|
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(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
3 - 5 |
Voltage is not applied between terminals 1 and 2 |
10 kΩ or higher |
|
3 - 5 |
Voltage is applied between terminals 1 and 2 |
Below 1 Ω |
| NG | |
REPLACE H-LP LO RELAY |
|
|
3. |
CHECK HARNESS AND CONNECTOR (BATTERY - H-LP LO RELAY) |
(a) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
Relay terminal 2 - Body ground |
Always |
11 to 14 V |
|
Relay terminal 5 - Body ground |
Always |
11 to 14 V |
| NG | |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
4. |
CHECK HARNESS AND CONNECTOR (H-LP LO RELAY - DRIVER SIDE JUNCTION BLOCK) |
(a) Disconnect the 1F driver side junction block connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
Relay terminal 1 - 1F-28 |
Always |
Below 1 Ω |
|
1F-28 - Body ground |
Always |
10 kΩ or higher |
| NG | |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
5. |
INSPECT DRIVER SIDE JUNCTION BLOCK |
|
(a) Remove the driver side junction block. |
|
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
1F-28 - MB-15 (HRLY) |
Always |
Below 1 Ω |
|
1F-28 - Body ground |
Always |
10 kΩ or higher |
|
*a |
Component without harness connected (Driver Side Junction Block) |
| OK | |
REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
| NG | |
REPLACE DRIVER SIDE JUNCTION BLOCK |
High Beam Headlight Circuit
DESCRIPTION
The main body ECU (multiplex network body ECU) controls the high beam headlights.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
Inspect the fuses for circuits related to th ...
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