2001 TOYOTA PRIUS battery

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

F12444
ON
WA
B11
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±441
2001 PRIUS (RM778U)
5 Check battery positive voltage.
CHECK:
Check the battery positive voltage.
OK:
Voltage: 10 ± 14 V
NG Check and repair charging system (See page
HV±39).
OK
6 Check operation of the ABS warning light.
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 ACTIVE TEST mode on the TOYOTA hand±held tester.
CHECK:
Check that ºONº and ºOFFº of the ABS warning light can be shown on the combination meter by the TOYOTA
hand±held tester.
In case of not using the TOYOTA hand±held tester:
(a) Disconnect the connector (B11) from the brake ECU.
(b) Using service wire, connect terminal WA of brake ECU
harness side connector and body ground.
(c) Turn the ignition switch ON.
OK:
ABS warning light goes off.
OK Check and replace brake ECU.
NG
Check for short circuit in harness and connector between combination meter and brake ECU,
combination meter and DLC3 (See page IN±41).
Check ABS solenoid relay circuit (See page DI±376).

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

F00043
1 2 3
4 5 6
1 2 3
4 5 6
1 2 3
4
65 Open
Continuity
Continuity
Continuity
Open
(+)(±)
(+) (±)1 2 3
4 5 6 Continuity
DI±444
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
3 Check ABS solenoid relay.
PREPARATION:
Remove the ABS solenoid relay from engine room R/B No. 3.
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
CHECK:
Connect the
test lead to terminal 5 and the  lead to terminal
3. Check continuity between the terminals.
OK:
Continuity
If there is no continuity, connect the  test lead to terminal 5
and the
lead to terminal 3. Recheck continuity between ter-
minals.
NG Replace ABS solenoid relay.
OK
Repair or replace and check for open circuit in harness and connector between DLC3 and ABS
solenoid relay and body ground (See page IN±41).

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

F02192
1
2
(+) (±)
DI±450
± 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 operation of the brake warning buzzer.
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 that brake warning buzzer sounds ºONº and ºOFFº with the TOYOTA hand±held tester.
OK Check and replace brake ECU.
NG
2 Check brake warning buzzer.
PREPARATION:
Disconnect the brake warning buzzer connector.
CHECK:
Apply battery positive voltage to the terminals 1 and 2 of
BRAKE warning buzzer connector, check that the brake warn-
ing buzzer sounds.
NG Replace brake warning buzzer.
OK

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