2001 TOYOTA PRIUS Service Repair Manual

F12410
LOCKON
PH
PHG
H8
DI±416
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
4 Check pressure switch (PH).
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 DATALIST mode on the TOYOTA hand±held tester.
CHECK:
Depress the brake pedal more than 40 times with the ignition switch OFF then turn the ignition switch ON
and check the pressure switch (PH) condition.
HINT:
When a pressure in power supply system is released, reaction force becomes heavy and stroke becomes
shorter.
OK:
ºOFFº turns to ºONº.
HINT:
OFF: Low pressure
ON: High pressure
In case of not using the TOYOTA hand±held tester:
PREPARATION:
(a) Disconnect the connector (H8) from the hydraulic brake
booster.
(b)
With the ignition switch OFF, depress the brake pedal more than
40 times to decrease the accumulator pressure.
HINT:
When a pressure in power supply system is released, reaction
force becomes heavy and stroke becomes shorter.
CHECK:
Measure resistance between terminals PH and PHG of hydrau-
lic brake booster connector.
OK:
Resistance: 1.0 kW
PREPARATION:
(a) Connect the connector (H8) to the hydraulic brake boost-
er.
(b) Disconnect the connector (H8) after ignition switch has
been ON and the pump motor has stopped.
CHECK:
Measure resistance between terminals PH and PHG of hydrau-
lic brake booster connector.
OK:
Resistance: 0 W
HINT:
After inspection, connect the connector and clear the DTC (See
page DI±353).
NG Replace hydraulic brake booster assembly.

F12411
LOCKONPL
PLG
H9
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±417
2001 PRIUS (RM778U)
OK
5 Check pressure switch (PL).
In case of using 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 DATALIST mode on the TOYOTA hand±held tester.
CHECK:
Depress the brake pedal more than 40 times with the ignition switch OFF then turn the ignition switch ON
and check the pressure switch (PL) condition.
HINT:
When a pressure in power supply system is released, reaction force becomes heavy and stroke becomes
shorter.
OK:
ºOFFº turns to ºONº.
HINT:
OFF: Low pressure
ON: High pressure
In case of not using TOYOTA hand±held tester:
PREPARATION:
(a) Disconnect the connector (H9) from the hydraulic brake
booster.
(b) With the ignition switch OFF, depress the brake pedal
more than 40 times to decrease the accumulator pres-
sure.
HINT:
When a pressure in power supply system is released, reaction
force becomes heavy and stroke becomes shorter.
CHECK:
Measure resistance between terminals PL and PLG of hydrau-
lic brake booster connector.
OK:
Resistance: 5.7 kW
PREPARATION:
(a) Connect the connector (H9) to the hydraulic brake boost-
er.
(b) Disconnect the connector (H9) after ignition switch has
been ON and the pump motor has stopped.
CHECK:
Measure resistance between terminals PL and PLG of hydrau-
lic brake booster connector.
OK:
Resistance: 1.0 kW

DI±418
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
HINT:
After inspection, connect the connector and clear the DTC (See
page DI±353).
NG Replace hydraulic brake booster assembly.
OK
6 Check for short circuit in harness and connector between pressure switch and
brake ECU (See page IN±41).
NG Repair or replace harness or connector.
OK

F00044
1
2
3 4
(+) (±) Continuity1 2
3 4
1
2
3 4 Open
Continuity
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±419
2001 PRIUS (RM778U)
7 Check hydro motor relay No. 1 and No. 2.
PREPARATION:
Remove the hydro motor relay No. 1 and No. 2 from the engine
room R/B No. 2.
CHECK:
Check continuity between each pair of terminal of motor relay.
OK:
Terminals 3 and 4Continuity
(Reference value *)
Terminals 1 and 2Open
*
Reference value:
Hydro motor relay No. 1 62 W
Hydro motor relay No. 2 54 W
CHECK:
(a) Apply battery positive voltage between terminals 3 and 4.
(b) Check continuity between terminals.
OK:
Terminals 1 and 2Continuity
NG Replace hydro motor relay.
OK
8 Check for short circuit in harness and connector between hydro motor relay No.
1, No. 2 and brake ECU (See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace brake ECU.