Page 959 of 1943
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
Page 961 of 1943
F00042
1 34
6 Open
(+)(±)1 2 3
4
4 5 6
1 2
3
2 5 6
5 Continuity
ContinuityContinuity
Open
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±383
2001 PRIUS (RM778U)
3 Check ABS solenoid relay.
CHECK:
Check continuity between each terminal of ABS solenoid relay.
OK:
Terminals 4 and 6Continuity
(Reference value 80 W)
Terminals 2 and 3Continuity
Terminals 1 and 3Open
CHECK:
(a) Apply battery positive voltage between terminals 4 and 6.
(b) Check continuity between each terminal of ABS solenoid
relay.
OK:
Terminals 2 and 3Open
Terminals 1 and 3Continuity
NG Replace ABS solenoid relay.
OK
Page 963 of 1943
F12673
B±G
F111
L4 Instrument
Panel J/B
DC/DC FL Block No. 1
3
Brake
Combination Meter
W±B
Brake Fluid
Level Warning
Switch7Brake ECU
LBL
C11
J7
J/C AM1162K
IE 2A
ID22B11
WR±Y
MAINLG±R
12
14
A W±G B±Y
IG1
RelayBRL
B12
C11
C10
C105 Body ECU
B8 B8
15
BR2
2 W±B
A A
J1
J/C AW±BInstrument
Panel J/B
Battery FL
Block
No. 21
F13
Ignition Switch
24
2H 2B 2D
2K2A 5 1
3 6
5 1
3
27
8GAUGE
LMultiplex Communication Circuit
IH 2B 6 1
J11
J/CGR±B GR
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±385
2001 PRIUS (RM778U)
DTC C1202/58 Brake Fluid Warning Switch Circuit
CIRCUIT DESCRIPTION
The brake fluid level warning switch sends the appropriate signal to the ECU when the brake fluid level drops.
HINT:
Depressing the parking brake pedal also turns on the brake warning light but does not diagnose DTC No.
C1202/58.
DTC No.DTC Detecting ConditionTrouble Area
C1202/58
When any of the following 1. 2. or 3. is detected:
1. When the ignition switch is ON, an open condition in the
reservoir level switch circuit continues for 2 sec. or
more.
2. While a vehicle is driven at a speed of 3 km/h (5 mph) or
more, decrease in the reservoir level continues for 10
sec. or more.
3. While a vehicle is stopped, decrease in the reservoir
level continues for 5 sec. or more.
Brake fluid level
Brake fluid level warning switch
Brake fluid level warning switch circuit
WIRING DIAGRAM
DI1GZ±10
Page 969 of 1943
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
Page 970 of 1943
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
Page 971 of 1943
F10937
GND+BS
DI±394
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
3 Check voltage of the ECU +BS 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 TOYOTA hand±held tester:
PREPARATION:
Remove the ABS ECU with connectors still connected.
CHECK:
Measure voltage between terminals +BS and GND of ABS ECU
connector.
OK:
Voltage: 10 ± 14 V
OK Check and replace brake ECU.
NG
4 Check for open circuit (to +BS) in harness and connector between brake ECU
and battery (See page IN±41).
NG Repair or replace harness or connector.
OK
Page 979 of 1943
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 DI±402
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
DTC C1241/41 IG Power Source Circuit
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
C1241/41
Either of the following 1. 2. or 3. is detected:
1. While a vehicle is driven at a speed of 3 km/h (5 mph),
the condition that the voltage of the terminal IG1 in brake
ECU is 9 V or less continues for 10 sec. or more.
2. When the solenoid relay is ON, the contact point of the
relay becomes OFF for 0.2 sec. or more due to the volt-
age decrease of the terminal IG1 in brake ECU.
3. When ignition switch is ON, the voltage of terminal IG1
in brake ECU remains in 17 V or more for 1.2 sec. or
more.
Battery
Charging system
Power source circuit
WIRING DIAGRAM
DI0WV±13
Page 980 of 1943
F12428
Instrument Panel J/B
ECU±IG
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±403
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
