Lexus RX300 (MCU15). Service manual — part 407

ELECTRONIC FUEL INJECTION

EFI SYSTEM

FI–1

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FUEL PUMP

FI–5

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FUEL PRESSURE REGULATOR

FI–15

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INJECTOR

FI–18

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FUEL TANK AND LINE

FI–26

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AIR FLOW METER

FI–28

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THROTTLE BODY

FI–32

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CAMSHAFT TIMING OIL

CONTROL VALVE

FI–39

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IDLE SPEED CONTROL (ISC) VALVE

FI–44

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ACOUSTIC CONTROL INDUCTION

SYSTEM (ACIS)

FI–50

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EFI MAIN RELAY

FI–55

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A/F SENSOR HEATER RELAY

FI–56

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CIRCUIT OPENING RELAY

FI–57

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VSV FOR EVAPORATIVE

EMISSION (EVAP)

FI–58

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VSV FOR ACOUSTIC CONTROL

INDUCTION SYSTEM (ACIS)

FI–60

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WATER TEMPERATURE SENSOR

FI–63

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KNOCK SENSOR

FI–64

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AIR–FUEL RATIO (A/F) SENSOR

FI–67

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OXYGEN SENSOR (Bank 1 Sensor 2)

FI–68

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ENGINE ECU

FI–70

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FUEL CUT RPM

FI–72

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FI0UO–01

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ELECTRONIC FUEL INJECTION

EFI SYSTEM

FI–1

LEXUS RX300 (RM785E)

EFI SYSTEM

PRECAUTION

1.

BEFORE WORKINR ON FUEL SYSTEM, DISCON-
NECT NEGATIVE (–) TERMINAL CABLE FROM BAT-
TERY

HINT:
Any diagnostic trouble code retained by the engine ECU will be
erased when the negative (–) terminal cable is removed from
the battery. Therefore, if necessary, read the diagnosis before
removing the negative (–) terminal cable from the battery.
2.

DO NOT SMOKE OR WORK NEAR AN OPEN FLAME
WHEN WORKING ON FUEL SYSTEM

3.

KEEP GASOLINE AWAY FROM RUBBER OR LEATH-
ER PARTS

4.

MAINTENANCE PRECAUTIONS

(a)

In event of engine misfire, these precautions should be
taken.
(1)

Check proper connection to battery terminals, etc.

(2)

After repair work, check that the ignition coil termi-
nals and all other ignition system lines are recon-
nected securely.

(3)

When cleaning the engine compartment, be espe-
cially careful to protect the electrical system from
water.

(b)

Precautions when handling oxygen sensor.
(1)

Do not allow oxygen sensor to drop or hit against an
object.

(2)

Do not allow the sensor to come into contact with
water.

5.

IF VEHICLE IS EQUIPPED WITH MOBILE RADIO
SYSTEM (HAM, CB, ETC.)

If the vehicle is equipped with a mobile communication system,
refer to the precaution in the IN section.
6.

AIR INDUCTION SYSTEM

(a)

Separation of the engine oil dipstick, oil filler cap, PCV
hose, etc. may cause the engine to run out of tune.

(b)

Disconnection, looseness or cracks in the parts of the air
induction system between the throttle body and cylinder
head will allow air suction and cause the engine to run out
of tune.

7.

ELECTRONIC CONTROL SYSTEM

(a)

Before removing EFI wiring connectors, terminals, etc.,
first disconnect the power by either turning the ignition
switch to LOCK or disconnecting the negative (–) terminal
cable from the battery.

HINT:
Always check the diagnostic trouble code before disconnecting
the negative (–) terminal cable from the battery.

FI2553

SST

B00679

Vinyl Bag

FI–2

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ELECTRONIC FUEL INJECTION

EFI SYSTEM

LEXUS RX300 (RM785E)

(b)

When installing the battery, be especially careful not to in-
correctly connect the positive (+) and negative (–) cables.

(c)

Do not permit parts to receive a severe impact during re-
moval or installation. Handle all EFI parts carefully, espe-
cially the engine ECU.

(d)

Be careful during troubleshooting as there are numerous
transistor circuit, and even slight terminal contact can
cause further troubles.

(e)

Do not open the engine ECU cover.

(f)

When inspecting during rainy weather, take care to pre-
vent entry of water. Also, when washing the engine
compartment, prevent water from getting on the EFI parts
and wiring connectors.

(g)

Parts should be replaced as an assembly.

(h)

Care should be taken when pulling out and inserting wir-
ing connectors.
(1)

Release the lock and pull out the connector, pulling
on the connectors.

(2)

Fully insert the connector and check that it is locked.

(i)

Use SST for inspection or test of the injector or its wiring
connector.
SST

09842–30070

8.

FUEL SYSTEM

(a)

When disconnecting the high fuel pressure line, a large
amount of gasoline will spill out, so observe these proce-
dures.
(1)

Disconnect the fuel pump connector.

(2)

Start the engine. After the engine has stopped on
its own, turn the ignition switch to LOCK.

(3)

Disconnect the fuel tube (See page FI–11).

(4)

Drain the fuel remained inside the fuel tube.

(5)

Prevent the disconnected fuel tube from damaging
and mixing foreign objects by covering them with a
vinyl bag.