2003 Lexus GX470 check engine

HOW TO USE THIS MANUAL
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HOW TO USE THIS MANUAL
The contents of this manual are explained briefly on this
page to help you make the best use of the manual. Please
read this page and the rest of the Owner’s Manual
carefully to make sure you fully understand the operation
of your vehicle.
This will help you enjoy safe and comfortable driving.
TABLE OF CONTENTS
The table of contents and the pictorial index provide easy
reference to the appropriate pages.
BASIC OPERATION QUICK REFERENCE
Operation of basic equipment is briefly explained in an easily
understandable way for quick reference.
SECTION 1 INSTRUMENTS AND CONTROLS
The vehicle’s equipment is divided into the 7 groups listed
below. Use of the equipment is explained, including any points
you should pay particular attention to.
1. Keys and doors
2. Switches
3. Gauges, meters and service reminder indicators
4. Interior equipment
5. Exterior equipment
6. Comfort adjustment
7. Theft deterrent
SECTION 2 AIR CONDITIONING AND AUDIO
The features of the vehicle’s air conditioning and audio are
explained in detail. Be sure to read this section so that you can
make full use of them.
SECTION 3 STARTING AND DRIVING
Starting the engine, driving, stopping, operation of features
affecting vehicle handling, hints on vehicle safety and safe
driving techniques are all explained. Please read everything
in this section, and remember − drive safely!
SECTION 4 IN CASE OF AN EMERGENCY
This section explains what to do in the event of an urgent
situation such as the engine not starting or getting a flat tire,
etc. If such a problem occu rs, check the contents of this
Owner’s Manual and follow the instructions given.
SECTION 5 MAINTENANCE
This section explains the importance of regular maintenance.
Regular and periodic inspection and maintenance of your
Lexus will help to keep your vehicle in its best condition.
SECTION 6 SERVICE PROCEDURES AND
SPECIFICATIONS
Simple maintenance procedure and service data are provided
here for your reference should you wish to perform inspection
and maintenance yourself.
INDEX
The page number is listed for each item in the Owner ’s Manual
so that you can rapidly find the item and page you are
searching for.

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GAUGES, METERS AND SERVICE REMINDER INDICATORS
44IF THIS INDICATOR OR
BUZZER COMES ON ...
DO THIS.
(k)Stop and check.
(l)Stop and check.
(m)Replace engine oil.
(n)Fill up tank.
(o)Add washer fluid.
(p)Key reminder buzzerRemove key.
(a) Brake System Warning Light and Buzzer
This light comes on in the following cases when the ignition key
is in the “ON” position.
 When the parking brake is applied ...
This light comes on for a few seconds when the ignition key is
in the “ON” position even after the parking brake is released.
 When the brake fluid level is low ...
CAUTION
It is dangerous to continue driving normally when the
brake fluid level is low.
When the hydraulic brake booster fails ...
If the hydraulic booster causes a problem resulting in poor
braking performance, the warning light comes on and buzzer
sounds continuously.
Have your vehicle checked at your Lexus dealer in the
following cases:
 The light does not come on even if the parking brake is
applied when the ignition key is in the “ON” position.
 The light does not come on even if the ignition key is turned
on with the parking brake released.
A warning light turning on briefly during operation does not
indicate a problem.

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GAUGES, METERS AND SERVICE REMINDER INDICATORS
47
(e) Malfunction Indicator Lamp
This lamp comes on when the ignition key is turned to the
“ON” position and goes off after the engine starts. This
means that the warning light system is operating properly.
If the lamp remains on, or the lamp comes on while driving,
first check the followings.
 Empty fuel tank
If the fuel tank is empty, refuel immediately.
 Loose fuel tank cap
If the fuel tank cap is loose, securely tighten it.
These cases are temporary malfunctions. The malfunction
indicator lamp will go off after taking several driving trips.
If the lamp will not go off even after the several trips, contact
your Lexus dealer as soon as possible.
If the fuel tank is not empty or the fuel tank cap is not
loose ...
 There is a problem somewhere in the engine, emission
control system, electronic throttle control system, automatic
transmission electrical system or warning light system itself.
Contact your Lexus dealer as soon as possible to service the
vehicle.
If the engine speed does not increase with the accelerator
pedal depressed down, there may be a problem somewhere
in your electronic throttle control system. At this time, vibration may occur. However, if you depress the
accelerator pedal more firmly and slowly, you can drive your
vehicle at low speeds. Have your vehicle checked by your
Lexus dealer as soon as possible.
Even if the abnormality of the electronic throttle control system
is corrected during low speed driving, the system may not be
recovered until the engine is stopped and the ignition key is
turned to “ACC” or “LOCK” position.
CAUTION
Be especially careful to prevent erroneous pedal
operation.
Emissions inspection and maintenance (I/M) programs
Your vehicle may not pass a state emission inspection if the
malfunction indicator lamp remains on. Contact your Lexus
dealer to check your vehicle’s emission control system and
OBD (On−Board Diagnostics) system before taking your
vehicle for the inspection.
For details, see “Emissions inspection and maintenance (I/M)
programs” on page 401.

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GAUGES, METERS AND SERVICE REMINDER INDICATORS
50
(j) “VSC TRAC” Warning Light
The light warns that there is a problem somewhere in the
following.
Vehicle skid control system
 Active traction control system
 Downhill assist control system
 Hill− start assist control system
The light will come on when the ignition key turned to “ON”, and
will go off after a few seconds.
It is not a malfunction that the warning light may stay on for 60
seconds after the ignition key is turned to the “ON” position.
Depressing the brake pedal repeatedly may turn on the lights.
It is normal if they go out after a few seconds.
There is no problem when the “VSC TRAC” warning light
comes on when the brake actuator temperature becomes high.
If the light comes on while driving, the above mentioned
systems do not work. However, as conventional braking
operates when applied, there is no problem to continue your
driving.
In the following cases, contact your Lexus dealer:
 The warning light does not come on after the ignition key is
turned to “ON”.
 The warning light remains on after the ignition key is turned
to “ON”.
 The warning light comes on while driving.
(k) Discharge Warning Light
This light warns that the battery is being discharged.
If it comes on while you are driving, stop the vehicle, turn off the
engine, and check for the cause. Look first at the engine drive
belt.
 If it is loose or broken, the generator will not charge the
battery properly.
 If the belt is O.K., there is a problem somewhere in the
charging system.
The engine ignition will continue to operate, however, until the
battery is discharged. Turn off the air conditioning, blower,
radio, etc., and drive directly to the nearest Lexus dealer or
repair shop.
NOTICE
Do not continue driving if the engine drive belt is broken
or loose.
(l) Low Engine Oil Pressure Warning Light
This light warns that the engine oil pressure is too low.
If it flickers or stays on while you are driving, pull off the road
to a safe place and stop the engine immediately. Call a Lexus
dealer or qualified repair shop for assistance.

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GAUGES, METERS AND SERVICE REMINDER INDICATORS
51
The light may occasionally flicker when the engine is idling or
it may come on briefly after a hard stop. There is no cause for
concern if it then goes out when the engine is accelerated
slightly.
The light may come on when the oil level is extremely low. It
is not designed to indicate low oil level, and the oil level must
be checked using the oil level dipstick.
NOTICE
Do not drive the vehicle with the warning light on even
for one block. It may ruin the engine.
(m) Engine Oil Replacement Reminder Light
This light reminds you when to replace the engine oil.
This light will come on when the ignition key is turned to “ON”
and will go off after about a few seconds.
When you drive for about 8000 km (5000 miles) after the
engine oil replacement, this light illuminates for about 3
seconds and then flashes for about 12 seconds with the
ignition key turned to “ON” position. If you continue driving
without the engine oil replacement, and if the driving range
exceeds
12000 km (7500 miles), the light will come on after the
ignition key is turned to “ON” position. The light will remain on
thereafter.
If the light is flashing, we recommend that you replace the
engine oil at an early opportunity depending on the driving and
road condition. If the light comes on, replace it as soon as
possible. You need to reset the light after the engine oil replacement.
Reset the light by following the procedure below:
1. Turn the ignition key to the “OFF” position with the odometer
reading
shown. (For details, see “Odometer and trip meter” on
page 42.)
2. Turn the ignition key to the “ON” position while holding down
the trip meter reset knob.
Hold down the knob until the light goes off. Before the light
goes off, it illuminates for 3 seconds, flashes for 2 seconds and
illuminates for 1 second.
If the system fails to reset, the light will remain flashing. In this
case, return to step 1 and try again.
(n) Low Fuel Level Warning Light
This light comes on when the fuel level in the tank becomes
very low. Fill the tank as soon as possible.
On inclines or curves, due to the movement of fuel in the tank,
the low fuel level warning light may come on earlier than usual.
(o) Low Washer Fluid Warning Light
This light comes on when the fluid level in the tank becomes
very low. Fill the tank as soon as possible.
(p) Key Reminder Buzzer
This buzzer reminds you to remove the key when you open the
driver’s door with the ignition key in the “ACC” or “LOCK”
position.

STARTING AND DRIVING
297
THREEWAY CATALYTICCONVERTERS
Threeway catalytic converters are emission control
devices installed in the exhaust system.
The purpose is to reduce pollutants in the exhaust gas.
CAUTION
Keep people and combustible materials away from
the exhaust pipe while the engine is running. The
exhaust gas is very hot.
 Do not drive, idle or park your vehicle over anything
that might burn easily such as grass, leaves, paper or
rags.
NOTICE
A large amount of unburned gases flowing into the
threeway catalytic converter may cause it to overheat
and create a fire hazard. To prevent this and other
damage, observe the following precautions:
 Use only unleaded gasoline.
 Do not drive with an extremely low fuel level; running
out of fuel could cause the engine to misfire, creating
an excessive load on the threeway catalytic
converter.
 Do not allow the engine to run at idle speed for more
than 20 minutes.
 Avoid racing the engine.
 Do not pushstart or pullstart your vehicle.
 Do not turn off the ignition while the vehicle is
moving.
 Keep your engine in good running order.
Malfunctions in the engine electrical system, electric
ignition system or fuel system could cause an
extremely high threeway catalytic converter
temperature.
 If the engine becomes difficult to start or stalls
frequently, take your vehicle in for a checkup as
soon as possible. Remember, your Lexus dealer
knows your vehicle and its threeway catalytic
converter system best.

STARTING AND DRIVING
298
To ensure that the threeway catalytic converter and
the entire emission control system operate properly,
your vehicle must receive the periodic inspections
required by the Lexus Maintenance Schedule. For
scheduled maintenance information, refer to the
“Owner’s Manual Supplement / Scheduled
Maintenance”.
ENGINE EXHAUST CAUTION
CAUTION
Avoid inhaling the engine exhaust. It contains
carbon monoxide, which is a colorless and odorless
gas. It can cause unconsciousness or even death.
 Make sure the exhaust system has no holes or loose
connections. The system should be checked from
time to time. If you hit something, or notice a change
in the sound of the exhaust, have the system checked
immediately.
 Do not run the engine in a garage or enclosed area
except for the time needed to drive the vehicle in or
out. The exhaust gases cannot escape, making this
a particularly dangerous situation.
 Do not remain for a long time in a parked vehicle with
the engine running. If it is unavoidable, however, do
so only in an unconfined area and adjust the heating
or cooling system to force outside air into the vehicle.
 Keep the back door closed while driving. An open or
unsealed back door may cause exhaust gases to be
drawn into the vehicle.

STARTING AND DRIVING
299
To allow proper operation of your vehicle’s
ventilation system, keep the inlet grilles in front of the
windshield clear of snow, leaves, or other
obstructions.
 If you smell exhaust fumes in the vehicle, drive with
the windows open and the back door closed. Have
the cause immediately located and corrected.BEFORE STARTING THE ENGINE
1. Check the area around the vehicle before entering it.
2. Adjust seat position, seatback angle, head restraint height
and steering wheel angle.
3. Adjust the inside and outside rear view mirrors.
4. Lock all doors.
5. Fasten seat belts.
Remember to check that the service reminder indicators
function when turning the key to “ON”, and check the fuel
gauge to see that you have sufficient fuel.