2001 TOYOTA PRIUS instrument panel

F12683
Brake ECU
Instrument Panel J/B GAUGE 4
IH L FL Block No. 1
1
BatteryIgnition Switch
2
2
2K2A18
W
3AM1IP1
AABS
2A14 2B F11
C10
J11
J/CB±W
5WA
W±B W±G
2H 2D DC/DC
B±Y
1
FL Block
No. 2 B±G
F131
B11
1C10
C10L2
10
22
5 1
3
6
87
LCommbination
Mater
2B 6
IDBR MAIN DI±442
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
ABS Warning Light Circuit
CIRCUIT DESCRIPTION
If the ECU detects trouble, it lights the ABS warning light while at the same time prohibiting ABS control. At
this time, the ECU records a DTC in memory.
Connect terminals Tc and CG of the DLC3 to make the ABS warning light blink and output the DTC.
WIRING DIAGRAM
DI29F±14

F12684
Brake Fluid Level
Warning Switch
IG1
Relay FL Block No. 2
Body ECU
Multiplex Communication CircuitR±Y
BrakePKB
E
83
GAUGE5
WJ12
J/C Parking
Brake Switch
2 1
1C10
2A7
LG±R
A 4BRL Brake ECU
W±GB12
6
Battery
IE LBL B12 B1113
R±Y R±Y
R±Y E
J7
J/C
J1
J/C
J11
J/C 2D2B
2H2K
2K5
23 15
2A7 AM1
C10C11C11
143
2
22 2
W±BB±Y
L
BRA A
A
W±BW±B 21 IA2 18
MAIN
B±GFL Block No. 1
111
DC/DC
F13 F11
B8 B8 15 164 Instrument
Panel J/B
LGR GR±B Ignition Switch
Instrument
Panel J/B
Commbination Meter
2B6
IH ID DI±446
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
BRAKE Warning Light Circuit
CIRCUIT DESCRIPTION
The BRAKE warning light lights up when the brake fluid is insufficient, the parking brake is applied or the
EBD is defective.
The BRAKE warning light also lights up when DTC No. C1213/63 or C1259/59 is detected, however, the EBD
is not inhibited in this case.
WIRING DIAGRAM
DI29G±14

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

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

F12687
DLC3
2DTs 4
Ts
8
4 CG14ID1GR±G
B11
W±B
AJ11
J/C
A
ID
C Instrument Panel J/BBrake ECU
J16
J/C
J24
J/CB
W±B W±B
A2K 8 3
GR±G GR±G
B DI±454
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
Ts Terminal Circuit
CIRCUIT DESCRIPTION
The sensor check circuit detects abnormalities in the speed sensor signal which cannot be detected by the
DTC check.
Connecting terminals Ts and CG of the DLC3 starts the check.
WIRING DIAGRAM
DI29J±12

F12837
IDE6
2H
2B
2D5
42 3EMPS ECU
IG
IG S/W
Battery ECU±IG
W
IG B±GB±Y 1
23
6
DC/DC AM1
PGND 5J/C
J15
J14DE
W±B
W±B J11
J/C A
F11 B±Y
W±G B±Y
1 IG1 Relay
2
2I
2K8
F18 FL Block No. 2
FL Block No. 1
F1311
1
2
E5 A J17
J/C Instrument Panel J/B
MAIN
± DIAGNOSTICSELECTRIC MOTOR POWER STEERING
DI±481
2001 PRIUS (RM778U)
DTC C1551/51 IG Power Source Circuit Malfunction
CIRCUIT DESCRIPTION
The EMPS ECU identifies ON or OFF status of ignition switch by this circuit.
DTC No.DTC Detecting ConditionTrouble Area
C1551/51The abnormal IG voltage value which is not within the specifi-
cation is input to EMPS ECU.
EMPS ECU

Power source circuit

Charging system
WIRING DIAGRAM
DI7R7±01

F12823
ECU±IG Fuse
Instrument Panel J/B
DI±482
± DIAGNOSTICSELECTRIC MOTOR POWER STEERING
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check ECU±IG fuse.
PREPARATION:
Remove the ECU±IG fuse from the instrument panel J/B.
CHECK:
Check the continuity of the ECU±IG.
OK:
Continuity
NG Check for short circuit in all harness and com-
ponents connected to ECU±IG fuse (See at-
tached wiring diagram).
OK
2 Check that the battery positive voltage when IG switch is OFF.
OK:
Voltage: 9 ± 14 V
NG Charge or replace the battery.
OK

F12839
PIG
RLY E5
E61
2 B
GR IM1
IA21
7 B
GR 3
3 3
31 35
2 EMPS Relay
R±G B±R
Instrument Panel J/B
ECU±B
6
2G 2H1
W
F111
F101
WFL Block No. 1
DC/DC
F131
Engine Room R/B No. 3
3
321EMPS
FL Block No. 2 F18
MAIN
1
E52
PGND W±B
A J17
J/C
IG BatteryEngine Room R/B No. 3 DI±484
± DIAGNOSTICSELECTRIC MOTOR POWER STEERING
2001 PRIUS (RM778U)
DTC C1552/52 PIG Power Source Circuit
CIRCUIT DESCRIPTION
When turning ignition switch ON, battery voltage is supplied to terminal PIG of EMPS ECU by EMPS relay
operation.
DTC No.DTC Detecting ConditionTrouble Area
C1552/52The abnormal motor power source voltage value which is not
within the specification is input to EMPS ECU.
EMPS ECU

Power source circuit
WIRING DIAGRAM
DI7R8±01