Lexus RX300 (MCU15). Service manual - part 219

DI–108

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DIAGNOSTICS

ENGINE

LEXUS RX300   (RM785E)

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.*

*: 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

Replace engine ECU.

A11663

VV1, VV2 and NE Signal Waveforms

2 V
/Division

20 msec./Division (Idling)

VV1

NE

VV2

GND

GND

GND

–

DIAGNOSTICS

ENGINE

DI–109

LEXUS RX300   (RM785E)

DTC

P1350

VVT Sensor/Camshaft Position Sensor Cir-
cuit Malfunction (Bank 2)

CIRCUIT DESCRIPTION

Refer to DTC P1346, P1351 on page DI–102.

DTC No.

DTC Detecting Condition

Trouble Area

No VVT sensor (Camshaft position sensor) signal to engine

ECU during cranking at 4 sec. or more

S Open or short in VVT sensor (camshaft position sensor) cir-

P1345

P1350

No VVT sensor (Camshaft position sensor) signal to engine

ECU with 5 sec. or more engine speed 600 rpm or more

cuit

S VVT sensor (camshaft position sensor)

S Camshaft timing gear

While crankshaft rotates twice, VVT sensor (Camshaft position

sensor) signal will be input to engine ECU 5 times.

S Camshaft timing gear

S Engine ECU

WIRING DIAGRAM

Refer to DTC P0335 on page DI–67.

INSPECTION PROCEDURE

HINT:
Read freeze frame data using hand–held tester or OBD 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 was warmed up or not, the air–fuel ratio was lean or rich, etc.
at the time of the malfunction.

1

Check resistance of VVT sensor (See page IG–1).

Reference: INSPECTION USING OSCILLOSCOPE
During idling, check the waveforms between terminals VV1 and
NE+, and VV2 and NE– of the engine ECU connector.
HINT:

S

The correct waveforms are as shown.

S

The waveform frequency is shortened as the engine
speed becomes higher.

NG

Replace VVT sensor.

OK

DI84G–02

DI–110

–

DIAGNOSTICS

ENGINE

LEXUS RX300   (RM785E)

2

Check for open and short in harness and connector between engine ECU and
VVT sensor (See page IN–32).

NG

Repair or replace harness or connector.

OK

3

Inspect sensor installation and signal plate teeth of camshaft timing gear.

NG

Tighten sensor. Replace camshaft timing gear.

OK

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

A14519

FL Block

Battery

S10
Stop Light
Switch

ALT

F11

STOP

2

1

5E

5

L2 
Light Failure Sensor

7

2

To Stop Light

E9

22

STP

11

W

1

5B

5B

4

9

1E

1

1A

G–W

G–O

J/B No. 5

G–B

IA1

G–W

G–W

G–R

W

5

3

Instrument Panel J/B

ST+

ST–

Engine ECU

–

DIAGNOSTICS

ENGINE

DI–111

LEXUS RX300   (RM785E)

DTC

P1520

Stop Light Switch Signal Malfunction

CIRCUIT DESCRIPTION

This signal is used to detect when the brakes have been applied. The STP signal voltage is the same as
the voltage supplied to the stop lights.
The STP signal is used mainly to control the fuel cut–off engine speed (The fuel cut–off engine speed is re-
duced slightly when the vehicle is braking.).

DTC No.

DTC Detecting Condition

Trouble Area

P1520

Stop light switch does not turn off when repeating driving at 30

km or more 10 time or more after depressing brake (2 trip

detection logic)

S Short in stop light switch signal circuit

S Stop light switch

S Engine ECU

WIRING DIAGRAM

INSPECTION PROCEDURE

HINT:
Read freeze frame data using hand–held tester or OBD 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 was warmed up or not, the air–fuel ratio was lean or rich, etc.
at the time of the malfunction.

1

Check operation of stop light.

CHECK:
Check if the stop lights go on and off normally when the brake pedal is operated and released.

NG

Check and repair stop light circuit.

DI088–12