engine TOYOTA PRIUS 2001 Service Repair Manual

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).

± DIAGNOSTICSENGINE
DI±153
2001 PRIUS (RM778U)
DTC P3190 Poor Engine Power
DTC P3191 Engine dose not Start
CIRCUIT DESCRIPTION
From the HV ECU, the ECM receives data such as power output required for the engine (required output),
estimated torque produced by the engine (estimated torque), engine RPM of control target (target RPM),
whether the engine is in start mode or not. Then, based on the required output and target RPM, the ECM
calculates a target torque that is to be produced by the engine and compares it with the estimated torque.
If the estimated torque is very low compared with the target torque, or the engine start mode continues at
the engine RPM or for the duration calculated by water temperature, an abnormal condition is detected.
DTC No.DTC Detecting ConditionTrouble Area
P3190
Following condition (a) to (e) continues at a fixed engine RPM
or a fixed length of time:
(a) Communication with HV ECU is normal.
(b) Engine RPM is a fixed value or more.
(c) Engine star mode is not active.
(d) Target torque is a fixed value or more.
(e) Ratio of estimated torque against target torque is less than
20 %.

Air induction system

Throttle body

Fuel pressure

Engine

Air flow meter

Out of fuel
Wt t
P3191
Following condition (a) to (c) continues at a fixed engine RPM
or for a fixed length of time:
(a) Vommunication with HV ECU is normal.
(b) Engine RPM is a fixed value or more.
(c) Engine start mode is active.
Water temp. sensor

Crankshaft position sensor

Camshaft position sensor

ECM
WIRING DIAGRAM
Refer to DTC P1636 on page DI±146.
INSPECTION PROCEDURE
1 Are there any other codes begin output?
YES Go to relevant DTC chart.
NO
DI7T6±01

DI±154
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
2 Check remaining amount of fuel.
NG Supply fuel.
OK
3 Check air induction system (See page SF±1).
NG Repair or replace.
OK
4 Check for umusual noise or vibration when starting engine or racing.
NG Repair or replace.
OK
5 Check fuel pressure (See page SF±6).
NG Check and repair fuel pump and fuel pipe line
(See page SF±19).
OK
6 Check air flow meter (See page SF±22) and engine coolant temp. sensor
(See page SF±49).
NG Repair or replace.
OK

± DIAGNOSTICSENGINE
DI±155
2001 PRIUS (RM778U)
7 Check crankshaft position sensor and camshaft position sensor
(See page IG±1).
NG Repair or replace.
OK
8 Check throttle control motor and throttle position sensor (See page SF±24).
NG Repair or replace.
OK
Chack and replace ECM (See page IN±41).

A14058
ECM
+B 4
E8
BatteryW±RG±R
MREL 25 EFI Relay
I15 Ignition
SW EFI
IGSW 6
IE 1B35
AM2E9
J24 J25
J1
J/CE10 B
9 3
B
2C1 2
2G
24
A F121 3
1K 1F12 1A
1J 2
7 1
W±BW±R
B±W
B±G Engine Room J/B
F18
FL
Block
No. 2IA2
FL Block No. 19G±R
J7
J/C
B±W AM2 IG2
J/C Instrument
Panel J/B
F13 1
A
A W±BCB
MAIN
1 DI±156
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
ECM Power Source Circuit
CIRCUIT INSPECTION
When the ignition switch is turned on, battery positive voltage is applied to IG2 Relay, terminal IGSW of the
ECM and the EFI main relay (Marking: EFI MAIN) control circuit in the ECM sends a signal to terminal MREL
of the ECM switching on the EFI main relay.
This signal causes current to flow to the coil, closing the contacts of the EFI main relay and supplying power
to terminals +B of the ECM.
If the ignition switch is turned off, the ECM continues to switch on the EFI main relay for a maximum of 2
seconds for the initial setting of the IAC valve.
WIRING DIAGRAM
DI7DK±02

A13635
ON
+B
E1
(±) (+)
A13636
IGSW
(+) (±)
± DIAGNOSTICSENGINE
DI±157
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminals +B and E1 or ECM connectors.
PREPARATION:
(a) Remove the ECM with connector still connected (See
page SF±62).
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals +B and E1 of the ECM
connectors.
OK:
Voltage: 9 ± 14 V
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI±22).
NG
2 Check for open in harness and connector between terminal E1 of ECM connector
and body ground (See page IN±41).
NG Repair or replace harness or connector.
OK
3 Check voltage between terminal IGSW of ECM connector and body ground.
PREPARATION:
(a) Remove the ECM with connector still connected (See
page SF±62).
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminal IGSW of the ECM con-
nector and body ground.
OK:
Voltage: 9 ± 14 V
OK Go to step 6.
NG

A13630
Engine Room J/B
AM2 Fuse
DI±158
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
4 Check AM2 fuse.
PREPARATION:
Remove the AM2 fuse from the engine room J/B.
CHECK:
Check the continuity of the AM2 fuse.
OK:
Continuity
NG Check for short in all harness and components
connected to AM2 fuse (See attached wiring dia-
gram).
OK
5 Check ignition switch (See page BE±16).
NG Replace ignition switch.
OK
Check and repair harness and connector be-
tween battery and ignition switch, and igni-
tion switch and ECM.

A14004
MREL
(+) (±)
A13630
Engine Room J/B
EFI Fuse
± DIAGNOSTICSENGINE
DI±159
2001 PRIUS (RM778U)
6 Check voltage between terminal MREL of ECM connector and body ground.
PREPARATION:
(a) Remove the ECM with connector still connected (See
page SF±62).
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminal MREL of the ECM con-
nector and body ground.
OK:
Voltage: 9 ± 14 V
NG Check and replace ECM (See page IN±41).
OK
7 Check EFI1 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 harness and components
connected to EFI1 fuse (See attached wiring
diagram).
OK
8 Check EFI main relay (Marking: EFI MAIN) (See page SF±37).
NG Replace EFI main relay.
OK