check engine CHEVROLET TAHOE 2007 3.G Owner's Manual

Before Leaving on a Long Trip
Make sure you are ready. Try to be well rested. If
you must start when you are not fresh — such
as after a day’s work — do not plan to make too
many miles that rst part of the journey. Wear
comfortable clothing and shoes you can easily
drive in.
Is your vehicle ready for a long trip? If you keep it
serviced and maintained, it is ready to go. If it
needs service, have it done before starting out. Of
course, you will nd experienced and able
service experts in GM dealerships all across North
America. They will be ready and willing to help
if you need it.Here are some things you can check before a trip:Windshield Washer Fluid:Is the reservoir
full? Are all windows clean inside and outside?
Wiper Blades:Are they in good shape?
Fuel, Engine Oil, Other Fluids:Have you
checked all levels?
Lamps:Are they all working? Are the lenses
clean?
Tires:They are vitally important to a safe,
trouble-free trip. Is the tread good enough
for long-distance driving? Are the tires
all inated to the recommended pressure?
Weather Forecasts:What is the weather
outlook along your route? Should you
delay your trip a short time to avoid a major
storm system?
Maps:Do you have up-to-date maps?
396

Highway Hypnosis
Is there actually such a condition as highway
hypnosis? Or is it just plain falling asleep at the
wheel? Call it highway hypnosis, lack of
awareness, or whatever.
There is something about an easy stretch of road
with the same scenery, along with the hum of
the tires on the road, the drone of the engine, and
the rush of the wind against the vehicle that
can make you sleepy. Do not let it happen to you!
If it does, your vehicle can leave the road in
less than a second, and you could crash and be
injured.
What can you do about highway hypnosis? First,
be aware that it can happen.Then here are some tips:Make sure your vehicle is well ventilated, with
a comfortably cool interior.
Keep your eyes moving. Scan the road ahead
and to the sides. Check your vehicle’s mirrors
and instruments frequently.
If you get sleepy, pull off the road into a rest,
service, or parking area and take a nap, get
some exercise, or both. For safety, treat
drowsiness on the highway as an emergency.
397

Hill and Mountain Roads
Driving on steep hills or mountains is different
from driving in at or rolling terrain.If you drive regularly in steep country, or if you are
planning to visit there, here are some tips that
can make your trips safer and more enjoyable. See
Off-Road Driving on page 372for information
about driving off-road.
Keep your vehicle in good shape. Check all
uid levels and also the brakes, tires,
cooling system, and transmission. These parts
can work hard on mountain roads.
{CAUTION:
If you do not shift down, the brakes could
get so hot that they would not work well.
You would then have poor braking or
even none going down a hill. You could
crash. Shift down to let the engine assist
the brakes on a steep downhill slope.
398

You can run the engine to keep warm, but be
careful.
{CAUTION:
Snow can trap exhaust gases under your
vehicle. This can cause deadly CO
(carbon monoxide) gas to get inside. CO
could overcome you and kill you. You
cannot see it or smell it, so you might not
know it is in your vehicle. Clear away
snow from around the base of your
vehicle, especially any that is blocking the
exhaust pipe. And check around again
from time to time to be sure snow does
not collect there.
Open a window just a little on the side of
the vehicle that is away from the wind.
This will help keep CO out.
403

Turn Signals When Towing a Trailer
The arrows on your instrument panel will
ash whenever you signal a turn or lane change.
Properly hooked up, the trailer lamps will also
ash, telling other drivers you’re about to
turn, change lanes or stop.
When towing a trailer, the arrows on your
instrument panel will ash for turns even if the
bulbs on the trailer are burned out. Thus, you may
think drivers behind you are seeing your signal
when they are not. It’s important to check
occasionally to be sure the trailer bulbs are still
working.
Driving On Grades
Reduce speed and shift to a lower gearbefore
you start down a long or steep downgrade. If you
don’t shift down, you might have to use your
brakes so much that they would get hot and no
longer work well.You can tow in DRIVE (D). You may want to shift
the transmission to THIRD (3) or, if necessary,
a lower gear selection if the transmission shifts too
often (e.g., under heavy loads and/or hilly
conditions).
You may also want to activate the tow/haul mode
if the transmission shifts too often. See “Tow/Haul
Mode” earlier in this section for more information.
When towing at high altitude on steep uphill
grades, consider the following: Engine coolant at
higher altitudes will boil at a lower temperature
than at or near sea level. If you turn your engine
off immediately after towing at high altitude on
steep uphill grades, your vehicle may show signs
similar to engine overheating. To avoid this, let
the engine run while parked (preferably on
level ground) with the automatic transmission in
PARK (P) for a few minutes before turning
the engine off. If you do get the overheat warning,
seeEngine Overheating on page 473.
435

CAUTION: (Continued)
If the transfer case on four-wheel-drive
vehicles is in NEUTRAL, your vehicle will
be free to roll, even if your shift lever is in
PARK (P). So, be sure the transfer case is
in a drive gear — not in NEUTRAL.
When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal
down while you:
start your engine,
shift into a gear, and
release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the
chocks.
4. Stop and have someone pick up and store the
chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when
you’re pulling a trailer. See the Maintenance
Schedule for more on this. Things that are
especially important in trailer operation are
automatic transmission uid (don’t overll), engine
oil, axle lubricant, belts, cooling system and
brake system. Each of these is covered in this
manual, and the Index will help you nd them
quickly. If you’re trailering, it’s a good idea
to review these sections before you start your trip.
Check periodically to see that all hitch nuts and
bolts are tight.
437

Service........................................................ 444
Accessories and Modications................... 444
California Proposition 65 Warning.............. 445
Doing Your Own Service Work.................. 445
Adding Equipment to the Outside of
Your Vehicle.......................................... 446
Fuel............................................................. 446
Gasoline Octane........................................ 447
Gasoline Specications.............................. 447
California Fuel........................................... 447
Additives................................................... 448
Fuel E85 (85% Ethanol)............................ 449
Fuels in Foreign Countries........................ 450
Filling the Tank......................................... 451
Filling a Portable Fuel Container............... 455
Checking Things Under the Hood.............. 456
Hood Release........................................... 457
Engine Compartment Overview.................. 458
Engine Oil................................................. 459
Engine Oil Life System.............................. 462
Engine Air Cleaner/Filter............................ 464
Automatic Transmission Fluid.................... 466
Engine Coolant.......................................... 470Coolant Surge Tank Pressure Cap............ 473
Engine Overheating................................... 473
Overheated Engine Protection
Operating Mode..................................... 476
Cooling System......................................... 477
Engine Fan Noise..................................... 483
Power Steering Fluid ................................. 484
Windshield Washer Fluid........................... 485
Brakes...................................................... 486
Battery...................................................... 490
Jump Starting............................................ 491
Rear Axle.................................................... 496
Four-Wheel Drive........................................ 497
Front Axle................................................... 498
Headlamp Aiming........................................ 499
Bulb Replacement....................................... 502
Halogen Bulbs........................................... 502
Taillamps, Turn Signal, Stoplamps and
Back-up Lamps...................................... 502
License Plate Lamp................................... 504
Replacement Bulbs................................... 504
Section 5 Service and Appearance Care
441

Your vehicle has an airbag system. Before
attempting to do your own service work, see
Servicing Your Airbag-Equipped Vehicle on
page 106.
You should keep a record with all parts receipts
and list the mileage and the date of any service
work you perform. SeeMaintenance Record
on page 594.
Adding Equipment to the Outside of
Your Vehicle
Things you might add to the outside of your
vehicle can affect the airow around it. This may
cause wind noise and affect windshield washer
performance. Check with your dealer before
adding equipment to the outside of your vehicle.
Fuel
Use of the recommended fuel is an important part
of the proper maintenance of your vehicle. To
help keep the engine clean and maintain optimum
vehicle performance, GM recommends the use
of gasoline advertised as TOP TIER Detergent
Gasoline.
The 8th digit of the Vehicle Identication Number
(VIN) shows the code letter or number that
identies your vehicle’s engine. The VIN is at the
top left of the instrument panel. SeeVehicle
Identication Number (VIN) on page 562.
If your vehicle has the 5.3L V8 engine
(VIN Code 0) or the 5.3L V8 engine (VIN Code 3),
you can use either regular unleaded gasoline or
ethanol fuel containing up to 85% ethanol
(E85); also seeFuel E85 (85% Ethanol) on
page 449. In all other engines, use only regular
unleaded gasoline.
446

Gasoline Octane
Use regular unleaded gasoline with a posted
octane rating of 87 or higher. If the octane rating
is less than 87, you might notice an audible
knocking noise when you drive, commonly referred
to as spark knock. If this occurs, use a gasoline
rated at 87 octane or higher as soon as possible. If
you are using gasoline rated at 87 octane or
higher and you hear heavy knocking, the engine
needs service.
Gasoline Specications
At a minimum, gasoline should meet ASTM
specication D 4814 in the United States or
CAN/CGSB-3.5 in Canada. Some gasolines may
contain an octane-enhancing additive called
methylcyclopentadienyl manganese tricarbonyl
(MMT). General Motors recommends against the
use of gasolines containing MMT. SeeAdditives
on page 448for additional information.
California Fuel
If your vehicle is certied to meet California
Emissions Standards, it is designed to operate on
fuels that meet California specications. See
the underhood emission control label. If this fuel is
not available in states adopting California
emissions standards, your vehicle will operate
satisfactorily on fuels meeting federal
specications, but emission control system
performance may be affected. The malfunction
indicator lamp may turn on and your vehicle may
fail a smog-check test. SeeMalfunction Indicator
Lamp on page 253. If this occurs, return to
your authorized GM dealer for diagnosis. If it is
determined that the condition is caused by the type
of fuel used, repairs may not be covered by
your warranty.
447

Checking Things Under
the Hood
{CAUTION:
An electric fan under the hood can start up
and injure you even when the engine is not
running. Keep hands, clothing, and tools
away from any underhood electric fan.
{CAUTION:
Things that burn can get on hot engine
parts and start a re. These include
liquids like fuel, oil, coolant, brake uid,
windshield washer and other uids, and
plastic or rubber. You or others could be
burned. Be careful not to drop or spill
things that will burn onto a hot engine.
456