2001 TOYOTA PRIUS battery

F12408
BM2
BM1
GND2 GND1
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±415
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check operation of hydraulic brake booster pump motor.
PREPARATION:
Disconnect the 2 connectors from the hydraulic brake booster.
CHECK:
Connect battery positive
lead to BM1 or BM2 terminal and
battery negative  lead to GND1 or GND2 terminal of the hy-
draulic brake booster (pump motor) connector.
OK:
The operation sound of the pump motor should be
heard.
NG Go to step 9.
OK
2 Check for short circuit in harness and connector between BM1 or BM2 of hy-
draulic brake booster and hydro motor relay (See page IN±41).
NG Repair or replace harness or connector.
OK
3 Check for short circuit in harness and connector between MTT of hydraulic
brake booster and brake ECU (See page IN±41).
NG Repair or replace harness or connector.
OK

F00044
1
2
3 4
(+) (±) Continuity1 2
3 4
1
2
3 4 Open
Continuity
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±419
2001 PRIUS (RM778U)
7 Check hydro motor relay No. 1 and No. 2.
PREPARATION:
Remove the hydro motor relay No. 1 and No. 2 from the engine
room R/B No. 2.
CHECK:
Check continuity between each pair of terminal of motor relay.
OK:
Terminals 3 and 4Continuity
(Reference value *)
Terminals 1 and 2Open
*
Reference value:
Hydro motor relay No. 1 62 W
Hydro motor relay No. 2 54 W
CHECK:
(a) Apply battery positive voltage between terminals 3 and 4.
(b) Check continuity between terminals.
OK:
Terminals 1 and 2Continuity
NG Replace hydro motor relay.
OK
8 Check for short circuit in harness and connector between hydro motor relay No.
1, No. 2 and brake ECU (See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace brake ECU.

F12681
Brake ECU
B2
2 6
AA 1
1 ABS
No. 2
Engine Room J/B22
2 2
22
14
22
Y 1
3 FL
Block No. 12
2
J1
J/CL±O
5IA2
LG±R
13R1+
R2+ Y±B
W±L F12
IE2 G±W W±L
Battery 1B
6
H6 H6
B±G 1K
Hydraulic Brake
Booster7
W±BY±G14
3Y±G
MR2MR1
MTT
MT+
MT± 29
27
28
18 ABS
No. 3
FL
Block No. 2B
1K
F13H5
H6
H5
H5
H5
W±B W±B
AAY±B
B11
B13
B10
B13
B10
B10
B10
J7
J/CEngine
Room
R/B No. 2 Hydro
Motor
Relay
No. 2 Hydro
Motor
Relay
No. 1 1
23
43
4 2 1
G
MAIN DI±422
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
WIRING DIAGRAM

F12663
(+) (±)
Engine Room R/B No. 2LOCK
1
1
F00044
1
2
3 4
(+) (±) Continuity1 2
3 4
1
2
3 4 Open
Continuity
DI±424
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
3 Check voltage between terminal 1 of engine room R/B No. 2 (for hydro motor re-
lays) and body ground.
PREPARATION:
Remove the hydro motor relay No. 1 and No. 2 from the engine
room R/B No. 2.
CHECK:
Measure voltage between terminal 1 of engine room R/B No. 2
(for hydro motor relays) and body ground.
OK:
Voltage: 10 ± 14 V
NG Check and repair harness or connector.
OK
4 Check hydro motor relay.
CHECK:
Check continuity between each pair of terminal of motor relay.
OK:
Terminals 3 and 4Continuity
(Reference value *)
Terminals 1 and 2Open
* Reference value:
Hydro motor relay No. 1 62 W
Hydro motor relay No. 2 54 W
CHECK:
(a) Apply battery positive voltage between terminals 3 and 4.
(b) Check continuity between terminals.
OK:
Terminals 1 and 2Continuity
NG Replace hydro motor relay.
OK

F12408
BM2
BM1
GND1
GND1
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±431
2001 PRIUS (RM778U)
2 Check operation of hydraulic brake booster pump motor.
PREPARATION:
Disconnect the 2 connectors from the hydraulic brake booster.
CHECK:
Connect battery positive
lead to BM1 or BM2 terminal and
battery negative  lead to GND1 or GND2 terminal of the hy-
draulic brake booster (pump motor) connector.
OK:
The operation sound of the pump motor should be
heard.
NG Go to step 7.
OK

F12678
Ignition SwitchFL Block No. 1
BatteryB±Y
2 4
W±B
W±B
W±B J15
6 1
IG1
GND3
GND1 GND4 DC/DC
AM1
ECU±IG
IDJ/C
A
A AW±B
GND2
B10 F131
12
2B 1 B±G
IEBrake ECU
817 W±GW
Instrument Panel J/B31 2H 2I 2D
2KF11
FL
Block
No. 2B11 B11
B11
B10
J1
J/C J11
J/C6
68 J14
213
35
IG1
RelayB±Y
B±Y
W±BE D
MAIN
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±435
2001 PRIUS (RM778U)
DTC C1257/57 Power Supply Drive Circuit
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
C1257/57
After turning the ignition switch ON, open or short circuit in
circuit of power supply drive system inside ECU continues
for more than 1.5 sec.
Battery

Power source circuit
WIRING DIAGRAM
DI29D±07

F12428
Instrument Panel J/B
ECU±IG
DI±436
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check ECU±IG fuse.
PREPARATION:
Remove the ECU±IG fuse from instrument panel J/B.
CHECK:
Check continuity of ECU±IG fuse.
OK:
Continuity
NG Check for short circuit in all the harness and
components connected to ECU±IG fuse (See
attached wiring diagram).
OK
2 Check battery positive voltage.
OK:
Voltage: 10 ± 14 V
NG Check and repair the charging system (See
page HV±39).
OK

F12405
ON
IG1
GND
F12406
LOCK
GNDB11
B10
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±437
2001 PRIUS (RM778U)
3 Check voltage of the ECU IG power source.
In case of using the TOYOTA hand±held tester:
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 DATALIST mode on the TOYOTA hand±held tester.
CHECK:
Check the voltage condition output from the ECU displayed on the TOYOTA hand±held tester.
OK:
ºNormalº is displayed.
In case of not using the TOYOTA hand±held tester:
PREPARATION:
Remove the brake ECU with connectors still connected.
CHECK:
Turn the ignition switch ON, measure voltage between termi-
nals IG1 and GND of brake ECU connector.
OK:
Voltage: 10 ± 14 V
OK Check and replace brake ECU.
NG
4 Check continuity between terminal GND of brake ECU connector and body
ground.
PREPARATION:
Disconnect the 2 connectors (B10, B11) from the brake ECU.
CHECK:
Measure resistance between terminal GND of brake ECU har-
ness side connector and body ground.
OK:
Resistance: 1 W or less
NG Repair or replace harness or connector.
OK
Check for open circuit in harness and connector between brake ECU and battery (See page
IN±41).