2001 TOYOTA SEQUOIA horn

DI94R±07
I28393
Hood Courtesy Switch Engine Room J/B
 ECU±B Fuse
 Door No. 2 Fuse
 H±LP RH Fuse (*2)
 H±LP LH Fuse (*2)
 DRL Fuse (*1)
Rear Washer Motor
Horn
Headlight
Rear washer switch
Ignition Switch
 Key Unlock Switch
DLC3 Body ECU
Instrument Panel J/B
 ECU±IG Fuse
 RAD No. 2 Fuse
 FOG Fuse
 FOG LIGHT Relay
 POWER MAIN Relay
 WSH Fuse
 STOP Fuse
 TAILLIGHT Relay Back Door Power
Window SwitchTheft Horn
Engine Room R/B
No.2
 DIMMER Relay
 DRL No. 4 Relay
 H±LP RH Fuse (*1)
 H±LP LH Fuse (*1)
 H±LP RL Fuse (*1)
 H±LP LL Fuse (*1)
Fog Light
Wireless Door
Control Receiver Wireless Door Lock Buzzer
Combination Meter Memory Seat Switch
(*1): w/ Daytime Running Light
(*2): w/o Daytime Running Light (Located behind
the instrument panel)
(Located behind
the heater control panel)
 DOME Fuse
 HEAD Relay
 HORN Relay
 DOME Fuse
Automatic Light Control Sensor
Stop Light Switch
Remote Control Mirror SwitchGlass Breakage
Sensor Microphone Glass Breakage
Sensor ECU
Combination Switch
 Light Control Switch
 Headlight Dimmer Switch
 Fog Light Switch DI±1698
± DIAGNOSTICSBODY CONTROL SYSTEM
1892 Author: Date:
2005 SEQUOIA (RM1146U)
PARTS LOCATION

I28394
Parking Brake Switch
Door Lock Motor
Rear Power
Window Motor Courtesy Light
Switch
Courtesy LightRear Courtesy Light Switch Horn Switch
Stop Light Rear Room Light Front Map Light
Courtesy Light Rear Courtesy
Light Switch Door Lock Motor
Rear Power
Window MotorRear Window Control
Switch RH Door Lock Motor
Power Window Switch

Passenger Door ECU

Door Lock Control Switch

Power Window Switch
Stop Light
Power Window
Master Switch

Driver
Door ECU

Door Lock
Control Switch

Power
Window Switch

Window Lock
Switch
Door Lock Motor
Rear Window
Control Switch LH
± DIAGNOSTICSBODY CONTROL SYSTEM
DI±1699
1893 Author: Date:
2005 SEQUOIA (RM1146U)

DI94S±08
DI±1700
± DIAGNOSTICSBODY CONTROL SYSTEM
1894 Author: Date:
2005 SEQUOIA (RM1146U)
CIRCUIT INSPECTION
Power source circuit
CIRCUIT DESCRIPTION
This circuit provides power to operate the body ECU.
BDR terminal: Power source for door lock motor
S+B terminal: Power source for security horn
ACC terminal: Power source for accessory
BECU terminal: Power source for backing up body ECU
IG terminal: Power source for starting body ECU
WIG terminal: Power source for washer motor

I18735
1Body ECU
T1
Theft Deterrent Horn
IA114
R±G
B71
SH R±G DI±1734
± DIAGNOSTICSBODY CONTROL SYSTEM
1928 Author: Date:
2005 SEQUOIA (RM1146U)
Theft deterrent horn circuit
CIRCUIT DESCRIPTION
During warning of the theft deterrent system, the body ECU activates the theft deterrent horn.
WIRING DIAGRAM
DI57A±10

± DIAGNOSTICSBODY CONTROL SYSTEM
DI±1735
1929 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
HINT:
When using the hand±held tester, start the inspection from step 1 and when not using the hand±held tester,
start from step 2.
1 Check theft deterrent horn using hand±held tester.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch ON.
CHECK:
According to the display on the tester, perform the ºACTIVE TESTº.
BODY ECU:
ItemTest DetailsDiagnostic Note
SECURITY HORNTurn theft horn ON/OFFThis test is available only for vehicles equipped
with security horn.
OK:
The theft deterrent horn sounds or stops correctly when operating it through the hand±held tes-
ter.
OK Proceed to next circuit inspection shown in
problem symptoms table (See page DI±1686).
NG
2 Check theft deterrent horn (See page BE±92).
NG Replace theft deterrent horn.
OK

DI±1736
± DIAGNOSTICSBODY CONTROL SYSTEM
1930 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check wire harness and connector between theft deterrent horn and body ECU,
theft deterrent horn and body ground (See page IN±35).
NG Repair or replace wire harness or connector.
OK
Proceed to next circuit inspection shown in
problem symptoms table
(See page DI±1686).

I24147
B7
HORN HORN Relay
2
1Body ECU
1
2D18
HR
HORN
B5 B±Y
6 C9
Horn SW
B54 F10
FL Block H8
Horn (low)
1
1 B B8
2H
7
2F5
3W±R W±R19
IA1
26
Battery H7
Horn (high)Engine Room J/B
B DI±1764
± DIAGNOSTICSBODY CONTROL SYSTEM
1958 Author: Date:
2005 SEQUOIA (RM1146U)
Horn circuit
CIRCUIT DESCRIPTION
The vehicle horn sounds when the horn switch is pressed. It also sounds as an alarm for the theft deterrent
system when the body ECU detects any alert condition.
WIRING DIAGRAM
DI94T±08

± DIAGNOSTICSBODY CONTROL SYSTEM
DI±1765
1959 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
HINT:
When using the hand±held tester, start the inspection from step 1 and when not using the hand±held tester,
start from step 2.
1 Check vehicle horn using hand±held tester.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch ON.
CHECK:
According to the display on the tester, perform the ºACTIVE TESTº.
BODY ECU:
ItemTest DetailsDiagnostic Note
VEHICLE HORNTurn vehicle horn sound ON/OFF±
OK:
The horn sounds or stops correctly when operating it through the hand±held tester.
OK Proceed to next circuit inspection shown in
problem symptoms table (See page DI±1686).
NG
2 Check horn (See page BE±145).
NG Replace horn.
OK
3 Check horn switch (See page BE±145).
NG Replace horn switch.
OK