2001 TOYOTA PRIUS Service Repair Manual

F12685
ECU±IG12
W±B20
GND1 IG1
Relay FL Block No. 2
BUZZER Ignition Switch
83W
2 1G
4BZ
W±G
B11 6
Battery
IDB12
B10 13
B±YJ/C
J1
J/C J11
J/C 2D 2B
2I
2K2H
2
3 1
58
AM1
31 2
W±B B±Y
Instrument Panel J/B
IE A
AW±B17 MAIN
B±GFL Block No. 1
1
1
1DC/DC
F13F11
J15
6 Brake Warning Buzzer
GND2 GND4 GND3
B11
B10 IA2
W±B W±BD
E
J14 GBrake ECU
B±Y
A
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±449
2001 PRIUS (RM778U)
Brake Warning Buzzer Circuit
CIRCUIT DESCRIPTION
The brake warning buzzer sounds while the accumulator pressure is abnormally low.
WIRING DIAGRAM
DI29H±07

F02192
1
2
(+) (±)
DI±450
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
HINT:
Start the inspection from step 1 in case of using the TOYOTA hand±held tester and start from step 2 in case
of not using the TOYOTA hand±held tester.
1 Check operation of the brake warning buzzer.
PREPARATION:
(a) Connect the TOYOTA hand±held tester to the DLC3.
(b) Turn the ignition switch ON, and push the TOYOTA hand±held tester main switch ON.
(c) Select the ACTIVE TEST mode on the TOYOTA hand±held tester.
CHECK:
Check that brake warning buzzer sounds ºONº and ºOFFº with the TOYOTA hand±held tester.
OK Check and replace brake ECU.
NG
2 Check brake warning buzzer.
PREPARATION:
Disconnect the brake warning buzzer connector.
CHECK:
Apply battery positive voltage to the terminals 1 and 2 of
BRAKE warning buzzer connector, check that the brake warn-
ing buzzer sounds.
NG Replace brake warning buzzer.
OK

± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±451
2001 PRIUS (RM778U)
3 Check for open and short circuit in harness and connector between brake ECU
and brake warning buzzer (See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace brake ECU.

F12686
DLC3
2DTc 3
Tc
8
4 CG13ID1 P±B P±B
B11
W±B
AJ11
J/C
A
ID C
Instrument Panel J/BBrake ECU
J16
J/C J26
J/C
J24
J/CP±B P±B
E E
C
W±B W±B
A2K 82
F09678
CG TcDLC3 ON
(+) (±)
DI±452
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
Tc Terminal Circuit
CIRCUIT DESCRIPTION
Connecting terminals Tc and CG of the DLC3 causes the ECU to display the DTC by flashing the ABS warn-
ing light.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check voltage between terminals Tc and CG of DLC3.
PREPARATION:
Turn the ignition switch ON.
CHECK:
Measure voltage between terminal Tc and CG of DLC3.
OK:
Voltage: 10 ± 14 V
OK If ABS warning light does not blink even after Tc
and CG are connected, the ECU may be defec-
tive.
NG
DI29I±13

± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±453
2001 PRIUS (RM778U)
2 Check for open and short circuit in harness and connector between brake ECU
and DLC3, DLC3 and body ground (See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace brake ECU.