2001 TOYOTA PRIUS Service Repair Manual

± DIAGNOSTICSENGINE
DI±137
2001 PRIUS (RM778U)
Check and replace vacuum hose and tube
between check valve and actuator.
OBD II scan tool (excluding TOYOTA hand±held tester):
1 Check vacuum hoses and tube between intake manifold and actuator.
CHECK:
(a) Check that the vacuum hoses is connected correctly.
(b) Check the vacuum hose for looseness and disconnection.
(c) Check the vacuum hose and tube for cracks, holes and damage.
(d) Check the vacuum hose and tube for clog.
NG Repair or replace.
OK
2 Check for open and short in harness and connector between VSV (for HC adsob-
er and catalyst system) and ECM (See page IN±41).
NG Repair or replace harness or connector.
OK
3 Check VSV (for HC adsober and catalyst system) (See page SF±47).
NG Replace VSV.
OK

A14019
ONHCC
DI±138
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
4 Check vacuum stored in vacuum hose between check valve and actuator.
PREPARATION:
(a) Remove the ECM with connector still connected (See
page SF±62).
(b) Disconnect the vacuum hose from the vacuum sensor (for
HC adsober and catalyst system).
(c) Connect the MITYVAC (Hand±held vacuum pump) to the
vacuum hose.
CHECK:
(a) Connect the terminal HCC of the ECM and body ground.
(b) Apply a vacuum of 55 kPa (420 mmHg, 16.24 in.Hg).
(c) Check that the vacuum after 30 sec.
OK:
The vacuum is 25 Kpa (188 mmHg, 7.38 in.Hg) or
more.
OK Check and replace vacuum hose between
check valve and actuator.
NG
5 Check check valve.
NG Replace check valve.
OK
6 Check stored vacuum of VSV (See page SF±47).
NG Replace VSV for HC adsober and catalyst sys-
tem.
OK

± DIAGNOSTICSENGINE
DI±139
2001 PRIUS (RM778U)
7 Check stored vacuum of actuator (See page EC±13).
NG Replace actuator.
OK
Check and replace vacuum hose and tube
between check valve and actuator.

F02660
HV ECUECM
SPDO
SPHV O 6
10
E9 H14
± DIAGNOSTICSENGINE
DI±141
2001 PRIUS (RM778U)
DTC P1525 Resolver Vehicle Malfunction
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
P1525When signals of vehicle speed is not input from the resolver for
16 sec. or more while rurining at a speed of 20 km/h or more
ECM

HV ECU

Wire harness
WIRING DIAGRAM
DI7T3±01

A14010
(±) (+)SPHV
A07133
4.5 ± 5.5 V
0
DI±142
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminal SPHV of ECM and body ground.
PREPARATION:
(a) Remove the ECM with connector still connected (See
page SF±62).
(b) Drive the vehicle at 20 km/h (12 mph).
CHECK:
Measure the voltage between SPHV of engine ECU connector
and body ground.
OK:
Voltage is generated intermitlently.
OK Replace engine ECU.
NG
2 Check for open and short in harness and connector between SPHV of ECM and
SPDO of HV ECU.
NG Repair or replace harness or connector.
OK
Replace HV ECU.

A14034
Battery
MAIN
FL Block No. 1
F131
B±GEngine Room J/B
1B43
E8BATT ECM
12
1A F12R±W EFI
FL Block No. 2B
1
± DIAGNOSTICSENGINE
DI±143
2001 PRIUS (RM778U)
DTC P1600 ECM BATT Malfunction
CIRCUIT DESCRIPTION
Battery positive voltage is supplied to terminal BATT of the ECM even when the ignition switch is OFF for
use by the DTC memory and air±fuel ratio adaptive control value memory, etc.
DTC No.DTC Detecting ConditionTrouble Area
P1600Open in back up power source circuit
Open in back up power source circuit

ECM
HINT:
If DTC P1600 appear, the ECM does not store another DTC.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
Read freeze frame data using TOYOTA hand±held tester or OBD II scan tool. Because freeze frame records
the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining
whether the vehicle was running or stopped, the engine warmed up or not, the air±fuel ratio lean or rich, etc.
at the time of the malfunction.
DI6VN±02