engine TOYOTA PRIUS 2001 Service Repair Manual

F12672
Brake ECU
AST Engine Room R/B No. 3
ABS Solenoid
Relay 3 W
DC/DCW±R
Y±B
R1+
SR 14
W±BBrake Actuator FL
Block
No. 11
1
1ABS No. 1
F10
MAIN
BatteryA
A B±G
J7
J/CB±L
BS7
21
1
B±O 3
Engine Room
R/B No. 3
FL
Block
No. 2F13
A
IEJ1
J/C W±B
B10
B13 B11 B1
Brake
ECU 3
3 3
3 33
64
B2
B3 AST6 6
Y±B
19 2 1
R
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±381
2001 PRIUS (RM778U)
DTCC0278/11, C0279/12ABS Solenoid Relay Circuit
CIRCUIT DESCRIPTION
This relay supplies power to each ABS solenoid. After the ignition switch is turned ON, if the initial check is
OK, the relay goes on.
DTC No.DTC Detecting ConditionTrouble Area
C0278/11
When the terminal SR in brake ECU is 2 V or less, the ter-
minal AST in brake ECU continues to be in other than the
range from 10 ± 14 V for 0.2 sec. more.

ABS solenoid relay
C0279/12
When the voltage of the terminal SR in brake ECU is 10 ±
14 V, the terminal AST in brake ECU continues to be in the
range from 10 ± 14 V for 0.2 sec. more.

ABS solenoid relay

ABS solenoid relay circuit
WIRING DIAGRAM
DI290±08

F12662
LOCK
1 2
Engine Room R/B No. 3
DI±382
± 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 ABS solenoid relay operation.
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 the operation sound of the ABS solenoid relay when operating it with the TOYOTA hand±held tester.
OK:
The operation sound of the ABS solenoid relay should be heard.
OK Go to step 4.
NG
2 Check voltage between terminals 1 and 2 of engine room R/B No. 3 (for ABS so-
lenoid relay).
PREPARATION:
Remove the ABS solenoid relay from engine room R/B No. 3.
CHECK:
Measure the voltage between terminals 1 and 2 of engine room
R/B No. 3 (for ABS solenoid relay).
OK:
Voltage: 10 ± 14 V
NG Check and repair harness or connector.
OK

F12443
ABS Solenoid
RelayEngine Room R/B
No. 3
Brake
Actuator
Brake ECU
ASTBS3
ASTAST
DI±384
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
4 Check continuity between terminals 3 of engine room R/B No. 3 (for ABS sole-
noid relay) and terminal AST of brake ECU.
CHECK:
Check continuity between terminal 3 of engine room R/B No. 3
(for ABS solenoid relay) and terminal AST of brake ECU.
OK:
Continuity
HINT:
There is a resistance of approx. 33 W between terminals BS and
AST of the brake actuator.
NG Repair or replace harness or brake actuator.
OK
5 Check for open and short circuit in harness and connector between ABS sole-
noid relay and brake ECU (See page IN±41).
NG Repair or replace harness or connector.
OK
If the same code is still output after the DTC is deleted, check the contact condition of each con-
nection. If the connections are normal, the ECU may be defective.

F12676
B±G
F101
3 Engine Room R/B No. 3
DC/DC FL Block No. 1
7Brake ECU
L W22
+BS
B13
8 ABS No. 4
1
F13
Battery2
B3 1
8 1
7 B3
B3
B3B13
B13
B13 B13
LG
P
V1
16 L
3
1
2
FL
Block
No. 2
Brake ActuatorSLA+
SLA±
SLR+
SLR± MAIN DI±392
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
DTCC1215/15, C1216/16 Linear Solenoid Positive Voltage Malfunction
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
C1215/15
When any of the following 1. or 2. is detected:
1. When the ignition switch is ON, the condition that the
voltage of the terminal +BS in brake ECU is 2.5 V or
less continues for 0.5 sec. or more.
2. While a vehicle is driven at a speed of 3 km/h (5 mph) or
more, the condition that the voltage of the terminal +BS
in brake ECU is 9 V or less continues for 10 sec. or
more.

Battery

Charging system

Power source circuit
C1216/16
When the ignition switch is ON, the condition that the volt-
age of the terminal +BS in brake ECU is 17 V or more con-
tinues for 1.2 sec. or more.
WIRING DIAGRAM
DI7ON±01

F12445
Engine Room R/B No. 3
ABS No. 4
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±393
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check ABS No. 4 fuse.
PREPARATION:
Remove the ABS No. 4 fuse from engine room R/B No. 3.
CHECK:
Check continuity of ABS No. 4 fuse.
OK:
Continuity
NG Check for short circuit in all the harness and
components connected to ABS No. 4 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

F12679
Ignition Switch
2W±B
W±B 6
1IG2
GND3 GND1
GND4 AM2
W±BGND2
B10
F131 2
2B
7 1
B±GBrake ECU
17 W±R
31 2G
IJ2C
F12 MAINB11 B12
B11 B101
6
8 12
B±W
BatteryW±B
IEA
A
ID Instrument Panel J/B
J1
J/CJ11
J/C 1 95
FL Block No. 2FL Block No. 1B±W W±R
2G
IB Instrument Panel J/B
Engine Room J/B
B
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±405
2001 PRIUS (RM778U)
DTC C1242/42 IG2 Power Source Circuit
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
C1242/42
When the vehicle is driven at a speed of 3km/h (5 mph) or
more, an open condition in IG2 circuit in brake ECU contin-
ues for 7 sec. or more.
Battery

Charging system

Power source circuit
WIRING DIAGRAM
DI7OO±01

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
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±411
2001 PRIUS (RM778U)
DTC C1251/51 Hydraulic Brake Booster Pump Motor
Malfunction
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
C1251/51
Either of the following 1. or 2. is detected:
1. After turning the ignition switch ON, the current of more
than 28A flows to the motor for more than 1 sec.
2. After turning the ignition switch ON, less than 7A
change in current is detected more than 3 times in a row
when the motor is ON.
Hydraulic brake booster pump motor
WIRING DIAGRAM
DI298±06

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±414
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
DTC C1252/52 Hydraulic Brake Booster Pump Motor
ON Time Abnormally Long
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
C1252/52After turning the ignition switch ON, when the power is sup-
plied to the pump motor for more than 5 minutes.
Hydraulic brake booster pump motor

Hydraulic brake booster pump motor circuit

Pressure switch (PH or PL)
WIRING DIAGRAM
DI6AB±02

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