TOYOTA PRIUS 2001 Service Repair Manual

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

A13634
LOCK
BATT
(±)
(+)
A13630
Engine Room J/B
EFI Fuse
DI±144
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
1 Check voltage between terminal BATT of ECM connector and body ground.
PREPARATION:
Remove the ECM with connector still connected (See page
SF±62).
CHECK:
Measure voltage between terminal BATT of the ECM connector
and body ground.
OK:
Voltage: 9 ± 14 V
OK Check and replace ECM (See page IN±41).
NG
2 Check EFI fuse.
PREPARATION:
Remove the EFI fuse from the engine room J/B.
CHECK:
Check continuity of EFI fuse.
OK:
Continuity
NG Check for short in all the harness and
components connected to EFI fuse.
OK
Check and repair harness or connector
between battery and EFI fuse and ECM
(See page IN±41).

I06573
HV ECUECM
HTE+ Y 19 19
E9
H14
E9
H1429 18 HTE+
HTE±
HTE± BR DI±146
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
DTC P1636 HV ECU Malfunction
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
P1636When communication with HV ECU is interrupted for 1.5 sec.
or more
Wire harness

HV ECU

ECM
WIRING DIAGRAM
DI7T4±01

A14011
ON
HTE+
HTE±(±) (+)
A14012
2V/
Div.
GND
2m sec/
Div.
± DIAGNOSTICSENGINE
DI±147
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminal HTE+ and HTE± of ECM.
PREPARATION:
(a) Remove the ECM with connector still connected (See
page SF±62).
(b) Turn the ignition swith ON.
CHECK:
Measure voltage between terminal HTE+ and HTE± of the
ECM.
OK:
Reference: INSPECTION USING OSCILLOSCOPE
Turn the ignition swith ON, check waveform between terminals
HTE+ and HTE± of the ECM.
HINT:
The correct waveform is as shown.
OK Replace ECM.
NG
2 Check for open and short in harness and connector between HTE+ and HTE± of
ECM and HTE+ and HTE± of HV ECU (See page IN±41).
OK Replace HV ECU.
NG
Repair or replace harness or connector.

F02660
HV ECUECM
ESTPR±Y 8
16
E9 H14ESTP DI±148
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
DTC P1637 ESTP Signal Malfunction
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
P1637When signal of ESTP is not input from the HV ECU for 2 sec.
or more
Wire harness

HV ECU

ECM
WIRING DIAGRAM
DI7T5±01

A14013
START
ESTP
± DIAGNOSTICSENGINE
DI±149
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminal ESTP of ECM and body ground.
PREPARATION:
(a) Remove the ECM with connector still connected (See
page SF±62).
(b) Start the engine.
CHECK:
Measure voltage between terminal ESTP of ECM and body
ground.
OK:
Voltage: 9 ± 14 V
OK Replace ECM.
NG
2 Check for open and short in harness and connector between ESTP of ECM and
HV ECU (See page IN±41).
OK Replace HV ECU.
NG
Repair or replace harness or connector.

DI±150
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
DTC P1656 OCV Circuit Malfunction
CIRCUIT DESCRIPTION
Refer to DTC P1349 on page DI±121.
DTC No.DTC Detecting ConditionTrouble Area
P1656
P1663Open or short in oil control valve circuit

Open or short in oil control valve circuit

Oil control valve

ECM
WIRING DIAGRAM
Refer to DTC P1349 on page DI±121.
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.
TOYOTA hand±held tester
1 Check OCV circuit.
PREPARATION:
(a) Start the engine and warmed it up.
(b) Connect the TOYOTA hand±held tester and select VVT from ACTIVE TEST menu.
CHECK:
Check the engine speed when operate the OCV by the TOYOTA hand±held tester.
OK:
VVT system is OFF (OCV is OFF): Normal engine speed
VVT system is ON (OCV is ON): Rough idle or engine stalled
OK Check for intermittent problems
(See page DI±3).
NG
DI6VO±02

A14062
± DIAGNOSTICSENGINE
DI±151
2001 PRIUS (RM778U)
2 Check operation of OCV.
PREPARATION:
(a) Start the engine and warmed it up.
(b) Disconnect the OCV connector.
(c) Apply battery positive voltage between terminals of the
OCV.
CHECK:
Check the engine speed.
OK:
Rough idle or engine stalled.
NG Replace OCV.
OK
3 Check voltage between terminals OCV+ and OCV± of ECM connector
(See page DI±121).
NG Check and replace ECM (See page IN±41).
OK
4 Check for open and short in harness and connector between OCV and ECM
(See page IN±41).
NG Repair or replace.
OK
Check for intermitent problems
(See page DI±3).

A14062
DI±152
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
OBD II scan tool (excluding TOYOTA hand±held tester)
1 Check operation of OCV.
PREPARATION:
(a) Start the engine and warmed it up.
(b) Disconnect the OCV connector.
(c) Apply battery positive voltage between terminals of the
OCV.
CHECK:
Check the engine speed.
OK:
Rough idle or engine stalled
NG Replace OCV.
OK
2 Check voltage between terminals OCV+ and OCV± of ECM connector
(See page DI±121).
NG Check and replace ECM (See page IN±41).
OK
3 Check for open and short in harness and connector between OCV and ECM
(See page IN±41).
NG Repair or replace.
OK
Check for intermitent problems
(See page DI±3).