2001 TOYOTA PRIUS Service Repair Manual

± DIAGNOSTICSBODY CONTROL SYSTEM
DI±701
2001 PRIUS (RM778U)
OK
Proceed to next circuit inspection shown on
problem symptoms table
(See page DI±683).

I15492
B8BODY ECU
HR 10
Battery10A
HORNHorn Relay
2 13 5 Engine Room J/B
C14
Horn SW
(Comb. SW)
6 1
1
1 B229
D DB±R B±R
B±R
B±W
B±R
H4
Horn F18
FL Block No. 2
120A MAINB±G
F13 F121J 1F
1BID24
J20
J/C FL Block No. 1
1IA28
B±R DI±702
± DIAGNOSTICSBODY CONTROL SYSTEM
2001 PRIUS (RM778U)
Horn Circuit
CIRCUIT DESCRIPTION
The horn is connected to the body ECU and activated by the body ECU.
WIRING DIAGRAM
DI2A3±06

± DIAGNOSTICSBODY CONTROL SYSTEM
DI±703
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check horn (See page DI±697).
NG Replace the horn.
OK
2 Check wireharness and connector between horn relay and body ECU, battery
and horn relay (See page IN±41).
NG Repair or replace wireharness or connector.
OK
Proceed to next circuit inspection shown on
problem symptoms table (See page
DI±683).

I15493
1920
B8 B±W
SH B±W
IE1
T1
Theft
Deterrent
HornBody ECU DI±704
± DIAGNOSTICSBODY CONTROL SYSTEM
2001 PRIUS (RM778U)
Theft Deterrent Horn Circuit
CIRCUIT DESCRIPTION
When the theft deterrent system is activated, the relay in the ECU turns ON and OFF cycles of approximately
0.2 sec., causing the theft deterrent horn to blow (See the wiring diagram below).
In this condition, if any of the following operations is done, the relay in the ECU turns OFF, thus stopping
the theft deterrent horn from blowing:
(1) Unlock the front LH or RH door with key.
(2) Turn the ignition switch to ACC or ON position.
(3) Unlock the doors with the wireless door lock control system.
(4) Wait for approximately 60 seconds.
(5) Push the panic switch of the wireless door lock control system.
Except for the anti±theft purpose, the theft deferrent horn is used as a high±pitched horn.
WIRING DIAGRAM
DI7NQ±01

I11582
(±) (+)
1
I11583
(±)
1 (+)
± DIAGNOSTICSBODY CONTROL SYSTEM
DI±705
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
HINT:
The flow chart below is based on the premise that the horns blow normally whenever the horn switch is oper-
ated. If horn operation is not normal when the horn switch is operated, check the horn switch.
1 Check voltage between terminal 1 of theft deterrent horn connector and body
ground.
PREPARATION:
Remove the theft deterrent horn and disconnect the connector.
CHECK:
Measure voltage between terminal 1 of theft deterrent horn
connector and body ground.
OK:
Voltage: 10 ± 14 V
NG Check and repair harness and connector be-
tween HORN fuse and theft deterrent horn.
OK
2 Check theft deterrent horn.
CHECK:
Connect positive (+) lead to terminal 1 and negative (±) lead to
ground to theft deterrent horn connector.
OK:
Theft deterrent horn blows.
NG Replace theft deterrent horn.
OK

DI±706
± DIAGNOSTICSBODY CONTROL SYSTEM
2001 PRIUS (RM778U)
3 Check harness and connector between body ECU and theft deterrent horn (See
page IN±41).
NG Check and repair harness or connector.
OK
Check and replace body ECU.

I15508
Body ECU
Engine Room J/B
Instrument Panel J/B
F18 Fusible Link Block No.2
J/C
120A MAIN FL
Battery L6
Luggage
Compartment
Light SW L5
Luggage
Compartment
LightI16 Interior Light
P4 Front Personal Light7
22N1
R±B 1 2
L±Y J29E
J30DJ/C
L±Y
W±B
L±Y
L±Y
2M3
2G2
L±Y1J 715A DOME
1B2
B
W±B B BJ/C
BI 11 J30D
J29E
1
F131
F12Instrument Panel J/B
± DIAGNOSTICSBODY CONTROL SYSTEM
DI±707
2001 PRIUS (RM778U)
Illumination circuit
CIRCUIT DESCRIPTION
Receiving the courtesy signal from either of the door ECU, the Body ECU will make the interior light, ignition
light, and foot light come on.
WIRING DIAGRAM
DI6LX±03