Lexus RX300 (MCU15). Service manual - part 218

A02397

OCV Signal Waveform

1 m sec./Division

5 V/
Division

GND

(A)

(A)

(A)

DI–104

–

DIAGNOSTICS

ENGINE

LEXUS RX300   (RM785E)

Hand–held tester:

1

Check valve timing (See page EM–22).

NG

Repair valve timing.

OK

2

Check operation of OCV.

PREPARATION:
(a)

Start the engine and warmed it up.

(b)

Connect the hand–held tester and select VVT from ACTIVE TEST menu.

CHECK:
Check the engine speed when operate the OCV by the 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.

OK

VVT system is OK.*

*: DTC P1349 are 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 engine ECU 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 for-
eign object in the engine oil.

NG

3

Check voltage between terminals OCV+ and OCV– of engine ECU connector.

Reference: INSPECTION USING OSCILLOSCOPE
Turn the ignition switch ON, and check waveform between ter-
minals OCV+ and OCV– of the engine ECU connector.
HINT:

S

The correct waveform is as shown.

S

The waveform frequency (A) is lengthened as the engine
speed becomes higher.

–

DIAGNOSTICS

ENGINE

DI–105

LEXUS RX300   (RM785E)

NG

Check and replace engine ECU (See page
 IN–32).

OK

4

Check valve timing controller assembly (See page EM–43).

NG

Replace VVT controller assembly, and then 
go to step 5.

OK

5

Check oil control valve (See page FI–42).

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.

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.*

A06076

OCV Connector

(a)

(b)

DI–106

–

DIAGNOSTICS

ENGINE

LEXUS RX300   (RM785E)

*: DTC P1349 are 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 engine ECU 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 for-
eign object in the engine oil.

NG

Replace engine ECU

OBD scan tool (excluding hand–held tester):

1

Check valve timing (See page EM–22).

NG

Repair valve timing.

OK

2

Check operation of OCV.

PREPARATION:
Start the engine.
CHECK:
(a)

Check the engine speed when disconnecting the OCV
connector.

(b)

Check the engine speed when applying battery positive
voltage between terminals of OCV.

RESULT:

Result

Check (a)

Check (b)

1

Normal engine speed

Rough idle or engine stall

2

Except 1

2

Go to step 4.

1

A02397

OCV Signal Waveform

1 msec./Division

5 V/
Division

GND

(A)

(A)

(A)

–

DIAGNOSTICS

ENGINE

DI–107

LEXUS RX300   (RM785E)

3

Check voltage between terminals OCV+ and OCV– of engine ECU connector.

Reference: INSPECTION USING OSCILLOSCOPE
Turn the ignition switch ON, check waveform between terminals
OCV+ and OCV– of the engine ECU connector.
HINT:

S

The correct waveform is as shown.

S

The waveform frequency (A) is lengthened as the engine
speed becomes higher.

OK

VVT system is OK.*

*: DTCs P1349 are 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 engine ECU 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 for-
eign object in the engine oil.

NG

Check and replace engine ECU (See page
IN–32).

4

Check valve timing controller assembly.

NG

Replace VVT controller assembly, and then 
go to step 5.

OK

5

Check oil control valve (See page FI–42).

NG

Replace oil control valve, and then go to step 6.

OK