2001 TOYOTA PRIUS Service Repair Manual

F12410
LOCK ONPH
PHG
F12413
LOCKPHPHG
DI±432
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
3 Check pressure switch (PH) operation.
PREPARATION:
(a) Turn the ignition switch OFF, and depress the brake pedal
40 times or more.
HINT:
When a pressure in power supply system is released, reaction
force becomes heavy and stroke becomes shorter.
(b) Install the LSPV gauge (SST) to the rear wheel cylinder
and bleed air.
SST 09709±29018
CHECK:
While checking the voltage between terminals PH and PHG of
hydraulic brake booster, depress the brake pedal with force of
more than 343 N (35 kgf, 77 lbf) and turn the ignition switch ON,
then check the rear wheel cylinder pressure when voltage
changes from 6 V to 0 V.
OK:
12,553 ± 20,104 kpa (128 ± 205 kgf´cm2, 1,820 ± 2,916
psi)
CHECK:
While checking the resistance between terminals PH and PHG,
depress the brake pedal changing the force in the range of 197
N (20 kgf, 44 lbf) to 343 N (35 kgf, 77 lbf) and check the rear
wheel cylinder pressure when resistance changes from 0 kW to
1 kW between PH and PHG.
OK:
11,964 ± 18,240 kpa (122 ± 186 kgf´cm2, 1,735 ± 2,645
psi)
HINT:
After inspection, connect the connector, fill brake reservoir with
brake fluid and clear the DTC (See page DI±353).
OK Go to step 5.
NG

F12411
LOCKON
PLG PL
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±433
2001 PRIUS (RM778U)
4 Check for open circuit in harness and connector between pressure switch (PH)
and brake ECU (See page IN±41).
NG Repair or replace harness or connector.
OK
Replace hydraulic brake booster assembly.
5 Check pressure switch (PL) operation.
PREPARATION:
(a) Turn the motor switch OFF, and depress the brake pedal
40 times or more.
HINT:
When a pressure in power supply system is released, reaction
force becomes heavy and stroke becomes shorter.
(b) Install the LSPV gauge (SST) to the rear wheel cylinder
and bleed air.
SST 09709 ±29018
CHECK:
While checking the resistance between terminals PL and PLG
of hydraulic brake booster, depress the brake pedal with force
of more than 343 N (35 kgf, 77 lbf) and turn the ignition switch
ON, then check the rear wheel cylinder pressure when the re-
sistance changes from 5.7 kW to 1.0 kW.
OK:
9,022 ± 15,102 kpa (92 ± 154 kgf´cm2, 1,308 ± 2,190 psi)
CHECK:
While checking the resistance between terminals PL and PLG
of hydraulic brake booster, depress the brake pedal changing
the force in the range of 197 N (20 kgf, 44 lbf) to 343 N (35 kgf,
77 lbf) and check the rear wheel cylinder pressure when resis-
tance changes from 1.0 kW to 5.7 kW.
OK:
8,532 ± 13,337 kpa (87 ± 136 kgf´cm2, 1,237 ± 1,934 psi)
HINT:
After inspection, connect the connector, fill brake reservoir with
brake fluid and clear the DTC (See page DI±353).
NG Replace hydraulic brake booster assembly.
OK

DI±434
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
6 Check pressure switch (PH) and pressure switch (PL).
CHECK:
Compare the pressure value of the rear wheel cylinder measured in check pressure switch (PL) operation
with the one measured in check pressure switch (PH) operation.
OK:

Pressure when the voltage between PH and PHG becomes 6 to 0 V > pressure when the resis-
tance between PL and PLG becomes 5.7 kW to 1.0 kW.

Pressure when the resistance between PH and PHG becomes 0 kW to 1 kW > pressure when
the resistance between PL and PLG becomes 1.0 kW to 5.7 kW.
NG Replace hydraulic brake booster assembly.
OK
Check and replace brake ECU.
7 Check for open or short circuit in harness and connector between hydraulic
brake booster pump motor and hydraulic brake booster (See page IN±41).
NG Replace wire harness.
OK
8 Check hydraulic brake booster pump motor (See page BR±48).
NG Replace hydraulic brake booster pump motor.
OK
Replace
hydraulic brake booster.

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