2001 TOYOTA PRIUS instrument panel

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

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

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

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

F12680
Battery B±G F13 1
FL Block
No. 2 F11
1
H15
High Mounted
Stop Light 2HR±B STOP
C Instrument Panel J/B
W
2 1Stop Light Switch
G±W
5IB1 2K
2G±W
A
AJ14
J/C
G±W 9Brake ECU
STP
G±WB11
2 1
W±B9 1 2E
BI 1
BKR7
Stop Light RH
W±B W±BW±BJ30
5E
R6
Stop Light LH
G±W
J30
J31J31C
G±W
G±W W±B
C C
C
J32 J33J33J/C J/C1
FL Block
No. 1E
DC/DC
MAIN DI±408
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
DTC C1249/49 Stop Light Switch Circuit
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
C1249/49
When the ignition switch is ON, the condition that the termi-
nal STP in brake ECU is 3 ± 12 V continues for 1 sec. or
more.
Stop light switch

Stop light switch circuit
WIRING DIAGRAM
DI1GO±09

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

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
B11 B11
B11
B10
J1
J/C J11
J/C6
68 J14
213
35
IG1
RelayB±Y
B±Y
W±BE D
FL
Block
No. 2
MAIN
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±439
2001 PRIUS (RM778U)
DTC Always ON Malfunction in ECU
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
Always ON
Either of the following 1. or 2. is detected:
1. ECU connectors are disconnected from ECU
2. There is a malfunction in ECU internal circuit
Battery

Charging system

Power source circuit

Brake ECU
HINT:
There is a case that TOYOTA hand±held tester cannot be used when ECU is abnormal.
WIRING DIAGRAM
DI7OQ±01