2001 TOYOTA PRIUS Service Repair Manual

A09060
C2
Oil Control Valve
2 1Y±R
W±GECM
OCV+
OCV± 23
24
E7 E7
± DIAGNOSTICSENGINE
DI±121
2001 PRIUS (RM778U)
DTC P1349 VVT System Malfunction
CIRCUIT DESCRIPTION
VVT system controls the intake valve timing to proper timing in response to driving condition.
ECM controls OCV (Oil Control Valve) to make the intake valve timing properly, and, oil pressure controlled
with OCV is supplied to the VVT controller, and then, VVT controller changes relative position between the
camshaft and the crankshaft.
DTC No.DTC Detecting ConditionTrouble Area
P1349
Condition (a) or (b) continues for after the engine is
warmed up and engine speed at 400 ± 4,000 rpm :
(a) Valve timing does not change from of current valve timing
(b) Current valve timing is fixed.
Valve timing

Oil control valve

VVT controller assembly

ECM
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.
TOYOTA hand±held tester
1 Check valve timing (See page EM±21).
NG Repair valve timing.
OK
DI6VL±02

A02397
OCV Signal Waveform
1 m sec./Division5 V/
Division
GND
(A) (A) (A)
DI±122
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
2 Check operation of OCV.
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 OFF to ON (OCV OFF to ON):
Engine speed increases.
VVT system ON to OFF (OCV ON to OFF):
Engine is stalled.
HINT:
The change of engine speed lasts only few seconds.
OK VVT system is OK.*
*: DTC P1349 is also output after the foreign object is caught
in some part of the system in the engine oil and the system re-
turns to normal in a short time. As ECM controls so that foreign
objects are ejected, there is no problem about VVT. There is
also no problem since the oil filter should get the foreign object
in the engine oil.
NG
3 Check voltage between terminals OCV+ and OCV± of ECM connector.
Reference: INSPECTION USING OSCILLOSCOPE
Turn the ignition switch ON, check waveform between terminals
OCV+ and OCV± of the ECM connector.
HINT:

The correct waveform is as shown.

The waveform frequency (A) is lengthened as the engine
speed becomes higher.
NG Check and replace ECM (See page IN±41).
OK

± DIAGNOSTICSENGINE
DI±123
2001 PRIUS (RM778U)
4 Check VVT controller assembly (See page EM±33).
NG Replace VVT controller assembly, and then go
to step 5.
OK
5 Check oil control valve (See page SF±35).
NG Replace oil control valve, and then go to step 6.
OK
6 Check blockage of oil control valve, oil check valve and oil pipe No.1.
NG Repair or replace.
OK
7 Check whether or not DTC P1349 is stored.
PREPARATION:
(a) Clear the DTC (See page DI±3).
(b) Perform simulation test.
CHECK:
Check whether or not DTC P1349 is stored (See page DI±3).
OK:
DTC P1349 is not stored
OK VVT system is OK.*
*: DTC P1349 is also output after the foreign object is caught
in some part of the system in the engine oil and the system re-
turns to normal in a short time. As ECM controls so that foreign
objects are ejected, there is no problem about VVT. There is
also no problem since the oil filter should get the foreign object
in the engine oil.

A14061A14062A14465
OCV Connector
(a)
(b)
DI±124
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
NG
Replace ECM.
OBD II scan tool (excluding TOYOTA hand±held tester)
1 Check valve timing (See page EM±21).
NG Repair valve timing.
OK
2 Check operation of OCV.
PREPARATION:
Start the engine.
CHECK:
(a) Check the engine speed when disconnect the OCV con-
nector.
(b) Check the engine speed when apply battery positive volt-
age between terminals of OCV.
RESULT:
ResultCheck (a)Check (b)
1Normal engine speedRough idle or engine stall
2Except 1
2 Go to step 4.
1

A02397
OCV Signal Waveform
1 m sec./Division5 V/
Division
GND
(A) (A) (A)
± DIAGNOSTICSENGINE
DI±125
2001 PRIUS (RM778U)
3 Check voltage between terminals OCV+ and OCV± of ECM connector.
Reference: INSPECTION USING OSCILLOSCOPE
Turn the ignition switch ON, check waveform between terminals
OCV+ and OCV± of the ECM connector.
HINT:

The correct waveform is as shown.

The waveform frequency (A) is lengthened as the engine
speed becomes higher.
OK VVT system is OK.*
*: DTC P1349 is also output after the foreign object is caught
in some part of the system in the engine oil and the system re-
turns to normal in a short time. As ECM controls so that foreign
objects are ejected, there is no problem about VVT. There is
also no problem since the oil filter should get the foreign object
in the engine oil.
NG
Check and replace ECM (See page IN±41).
4 Check VVT controller assembly (See page EM±33).
NG Replace VVT controller assembly, and then go
to step 5.
OK
5 Check oil control valve (See page SF±35).
NG Replace oil control valve, and then go to step 6.
OK