TOYOTA PRIUS 2001 Service Repair Manual

R14205
1
2
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±373
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 output value of speed sensor.
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 that there is no difference between the speed value output from the speed sensor displayed on the
TOYOTA hand±held tester and the speed value displayed on the speedometer when driving the vehicle.
OK:
There is almost no difference from the displayed speed value.
HINT:
There is tolerance of ± 10 % in the speedometer indication.
OK Check and replace brake ECU.
NG
2 Check speed sensor.
Front:
PREPARATION:
(a) Remove the front fender liner.
(b) Make sure that there is no looseness at the connector
lock part and connecting part of the connector.
(c) Disconnect the speed sensor connector.
CHECK:
Measure resistance between terminals 1 and 2 of speed sensor
connector.
OK:
Resistance: 0.6 ± 2.5 kW
CHECK:
Measure resistance between terminals 1 and 2 of speed sensor
connector and body ground.
OK:
Resistance: 10 MW or higher

F10179
1
2
F10180
Connector 1
12
Connector 2
1
2
DI±374
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
Rear:
PREPARATION:
(a) Make sure that there is no looseness at the connector
lock part and connecting part of the connector.
(b) Disconnect the speed sensor connector at hub bearing .
CHECK:
Measure resistance between terminals 1 and 2 of speed sensor
connector.
OK:
Resistance: 0.7 ± 2.2 kW
CHECK:
Measure resistance between terminals 1 and 2 of speed sensor
connector and body ground.
OK:
Resistance: 1 MW or higher
Rear speed sensor sub±wire harness:
PREPARATION:
(a) Remove the seat cushion and seatback.
(b) Make sure that there is no looseness at the connector
lock part and connecting part of the connector.
(c) Disconnect the speed sensor connector inside vehicle.
CHECK:
(a) Measure resistance between terminal 1 of connector 1
and terninal 2 of connector 2.
(b) Measure resistance between terminal 2 of connector 1
and terninal 1 of connector 2.
OK:
Resistance: below 1 W
CHECK:
Measure resistance between terminals 1 and 2 of speed sensor
connector 1 and body ground.
OK:
Resistance: 10 MW or higher
NG Replace speed sensor or sub±wire harness.
NOTICE:
Check the speed sensor signal last (See page DI±353).
OK

BR3795F10178
F10452
Front
Rear OK
NG OKNG
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±375
2001 PRIUS (RM778U)
3 Check for open and short circuit in harness and connector between each speed
sensor and brake ECU (See page IN±41).
NG Repair or replace harness or connector.
OK
4 Check speed sensor installation.
CHECK:
Check the speed sensor installation.
OK:
The installation bolt is tightened properly and there is
no clearance between the sensor and steering
knuckle or rear axle carrier.
Torque:
Front speed sensor : 8.0 N´m (82 kgf´cm, 71 in.´lbf)
NG Replace speed sensor.
NOTICE:
Check the speed sensor signal last (See page DI±353).
OK

W04200
Normal Signal Waveform
1 V / Division2 m/s / DivisionGND
R00948
DI±376
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
5 Check speed sensor and sensor rotor serrations.
REFERENCE: INSPECTION USING OSCILLOSCOPE
PREPARATION:
(a) Remove the brake ECU with connectors still connected.
(b) Connect the oscilloscope to the terminals FR+, FL+, RR+
or RL+ and GND of the brake ECU.
CHECK:
Drive the vehicle with about 20 km/h (12 mph), and check the
signal waveform.
HINT:

As the vehicle speed (rpm of the wheels) increases, a
cycle of the waveform becomes shorter and the fluctua-
tion in the output voltage becomes greater.

When noise is identified in the waveform on the oscillo-
scope, error signals are generated due to the speed sen-
sor rotor's scratches, looseness or foreign matter depos-
ited on it.
OK Check and replace brake ECU.
NG
6 Check sensor rotor and sensor tip.
Front:
PREPARATION:
Remove the front drive shaft (See page SA±17).
CHECK:
Check the sensor rotor serrations.
OK:
No scratches or missing teeth or foreign objects.
PREPARATION:
Remove the front speed sensor (See page BR±53).
CHECK:
Check the sensor tip.
OK:
No scratches or foreign objects on the sensor tip.
HINT:
If foreign matter (including that on the sensor rotor side) is iden-
tified, remove it and after reassembling, check the output wave-
form.

W04846
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±377
2001 PRIUS (RM778U)
Rear:
PREPARATION:
Remove the rear speed sensor (See page BR±56).
CHECK:
Check the sensor rotor serrations.
OK:
No scratches or missing teeth or foreign objects.
HINT:
If the sensor rotor is damaged or deformed, replace the hub as-
sembly.
CHECK:
Check the sensor tip.
OK:
No scratches or foreign objects on the sensor tip.
HINT:
If foreign matter (including that on the sensor rotor side) is iden-
tified, remove it and after reassembling, check the output wave-
form.
NG Replace sensor rotor or speed sensor.
NOTICE:
Check the speed sensor signal last (See page DI±353).
OK
Check and replace brake ECU.

DI±378
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
DTCC0226/21 ± C0246/23ABS Solenoid Circuit
DTC
C1217/25 ± C1219/27Regenerative Solenoid Circuit
CIRCUIT DESCRIPTION
This solenoid goes on when signals are received from the ECU and controls the pressure acting on the wheel
cylinders thus controlling the braking force.
DTC No.DTC Detecting ConditionTrouble Area
C0226/21Open or short circuit in SFRH or SFRR circuit continues for
0.05 sec. or more.
SFRH or SFRR circuit

Brake actuator
C0236/22Open or short circuit in SFLH or SFLR circuit continues for
0.05 sec. or more.
SFLH or SFLR circuit

Brake actuator
C0246/23Open or short circuit in SRR or SRH circuit continues for
0.05 sec. or more.
SRR or SRH circuit

Brake actuator
C1217/25Open or short circuit in SMC1 circuit continues for 0.05 sec.
or more.
SMC1 circuit

Brake actuator
C1218/26Open or short circuit in SMC2 circuit continues for 0.05 sec.
or more.
SMC2 circuit

Brake actuator
C1219/27Open or short circuit in SS circuit continues for 0.05 sec. or
more.
SS circuit

Brake actuator
DI28Z±13

F12671
Brake ECU
SFRH
SFRR
SFLH
SFLR Engine Room
R/B No. 3
19
5 1121
4 W±R
2 1 4
3
7 14
IER1+
SR
8 W±B
F102
Brake Actuator 1
A
Battery10R±W
Y±B
G±W
G±O G±B
B39
32 5
12
R±Y ABS No. 1
BS
SFRR
SFLH
SFLR
SRRH
SRRR
SMC1
SS J1
J/C1
4 W
3 FL
Block
No. 1 2
1
B3 B3 B2
B3 B2 B3 B3B3B11 IA2
R±L R±G R±B SFRH
SMC2Y±B
Y±B
3
B10SRRH
SRRR
SMC1
SS SMC2 9
B10B10 B10B10 B10B10 B10B10 B10 B±L7
3
3
3
3 36
J7
J/C
W±B AA
B2 3
3Engine
Room
R/B No. 3
F131
1
B±G
1
FL
Block
No. 2ABS Solenoid Relay
R
DC/DC
MAIN
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±379
2001 PRIUS (RM778U)
WIRING DIAGRAM

F12666
SS
SFRHSFRR
SMC1
SFLH
SRRR SMC2
BS
SRRHSFLR
DI±380
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check brake actuator solenoid.
PREPARATION:
Disconnect the 2 connectors from the brake actuator.
CHECK:
Check continuity between the terminal BS and each of termi-
nals SFRH, SFRR, SFLH, SFLR, SRRH, SRRR, SMC1, SMC2
and SS of brake actuator connector.
OK:
Continuity
HINT:
Resistance of each solenoid at 20 °C (68 °F)
SFRH, SFLH, SRRH: approx. 6.6 W
SFRR, SFLR, SRRR: approx. 2.2 W
SMC1, SMC2, SS: approx. 16 W
NG Replace brake actuator.
OK
2 Check for open and short circuit in harness and connector between brake ECU
and brake actuator (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.

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