1999 GMC JIMMY check engine

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When you're turning with a trailer, make wider turns than
normal. Do this so your trailer won't strike soft shoulders,
curbs, road signs, trees or other objects. Avoid jerky or
sudden maneuvers. Signal well in advance.
Turn Signals When Towing a Trailer
When you tow a trailer, your vehicle has to have extra
wiring and a heavy
-duty turn signal flasher (included in
the optional trailering package).
The arrows on your instrument panel will flash
whenever you signal a turn or lane change. Properly
hooked up, the trailer lamps will also flash, telling other
drivers you're about to turn, change lanes or stop.
When towing a trailer, the arrows on your instrument
panel will flash 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 gear before 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.
On a long uphill grade, shift down and reduce your
speed to around 45 mph (70 km/h) to reduce the
possibility of engine and transmission overheating. If
you have an automatic transmission, you should use
THIRD (3) when towing a trailer. Operating your
vehicle in THIRD (3) when towing a trailer will
minimize heat buildup and extend the life of your
transmission. Or, if you have a manual transmission,
it's better not to use FIFTH (5) gear, just drive in
FOURTH (4) gear (or, as you need to, a lower gear).
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes. 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) (or the manual transmission out
of gear and the parking brake applied) for a few minutes
before turning the engine off. If you do get the overheat
warning, see ªEngine Overheatingº in the Index.

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4-55 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 fluid (don't
overfill), engine oil, axle lubricant, belt, cooling system
and brake system. Each of these is covered in this
manual, and the Index will help you find 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.

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5. Check that the jumper cables don't have loose or
missing insulation. If they do, you could get a shock.
The vehicles could be damaged too.
Before you connect the cables, here are some basic
things you should know. Positive (+) will go to
positive (+) and negative (
-) will go to a metal
engine part. Don't connect positive (+) to negative
(
-) or you'll get a short that would damage the
battery and maybe other parts too.
6. Connect the red
positive (+) cable to the
positive (+) terminal of
the vehicle with the
dead battery.
7. Don't let the other end
touch metal. Connect
it to the positive (+)
terminal of the
good battery.
8. Now connect the black
negative (
-) cable to
the good battery's
negative (
-) terminal.
Don't let the other end
touch anything until the
next step. The other end
of the negative cable
doesn't go to the
dead battery.
It goes to a heavy unpainted metal part on the engine of
the vehicle with the dead battery.

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Section 6 Service and Appearance Care
Here you will find information about the care of your vehicle. This section begins with service and fuel information,
and then it shows how to check important fluid and lubricant levels. There is also technical information about your
vehicle, and a part devoted to its appearance care.
6
-2 Service
6
-3 Fuel
6
-5 Fuels in Foreign Countries
6
-5 Filling Your Tank
6
-7 Filling a Portable Fuel Container
6
-8 Checking Things Under the Hood
6
-10 Engine Oil
6
-15 Engine Air Cleaner/Filter
6
-16 Automatic Transmission Fluid
6
-19 Manual Transmission Fluid
6
-20 Hydraulic Clutch
6
-21 Rear Axle
6
-22 Four-Wheel Drive
6
-24 Radiator Pressure Cap
6
-24 Thermostat
6
-24 Engine Coolant
6
-27 Power Steering Fluid
6
-28 Windshield Washer Fluid6
-29 Brakes
6
-33 Battery
6
-34 Bulb Replacement
6
-39 Windshield Wiper Blade Replacement
6
-41 Tires
6
-49 Appearance Care
6
-50 Cleaning the Inside of Your Vehicle
6
-52 Care of Safety Belts
6
-53 Cleaning the Outside of Your Vehicle
6
-57 GM Vehicle Care/Appearance Materials
6
-58 Vehicle Identification Number (VIN)
6
-58 Service Parts Identification Label
6
-59 Electrical System
6
-65 Replacement Bulbs
6
-65 Capacities and Specifications
6
-66 Air Conditioning Refrigerants
6
-66 Normal Maintenance Replacement Parts

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CAUTION:
You can be injured and your vehicle could be
damaged if you try to do service work on a
vehicle without knowing enough about it.

Be sure you have sufficient knowledge,
experience, the proper replacement parts
and tools before you attempt any vehicle
maintenance task.

Be sure to use the proper nuts, bolts and
other fasteners. ªEnglishº and ªmetricº
fasteners can be easily confused. If you use
the wrong fasteners, parts can later break
or fall off. You could be hurt.
Adding Equipment to the Outside of
Your Vehicle
Things you might add to the outside of your vehicle can
affect the airflow 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 regular unleaded gasoline rated at 87 octane or higher.
It is recommended that the gasoline meet specifications
which have been developed by the American Automobile
Manufacturers Association (AAMA) and endorsed by the
Canadian Motor Vehicle Manufacturers Association for
better vehicle performance and engine protection.
Gasolines meeting the AAMA specification could provide
improved driveability and emission control system
performance compared to other gasolines. For more
information, write to: American Automobile
Manufacturer's Association, 7430 Second Ave, Suite 300,
Detroit MI 48202.
Be sure the posted octane is at least 87. If the octane is
less than 87, you may get a heavy knocking noise when
you drive. If it's bad enough, it can damage your engine.
If you're using fuel rated at 87 octane or higher and you
hear heavy knocking, your engine needs service. But
don't worry if you hear a little pinging noise when
you're accelerating or driving up a hill. That's normal,
and you don't have to buy a higher octane fuel to get rid
of pinging. It's the heavy, constant knock that means
you have a problem.

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If your vehicle is certified to meet California Emission
Standards (indicated on the underhood emission control
label), it is designed to operate on fuels that meet
California specifications. If such fuels are not available
in states adopting California emissions standards, your
vehicle will operate satisfactorily on fuels meeting
federal specifications, but emission control system
performance may be affected. The malfunction indicator
lamp on your instrument panel may turn on and/or your
vehicle may fail a smog
-check test. (See ªMalfunction
Indicator Lampº in the Index.) If this occurs, return to
your authorized GM dealer for diagnosis to determine
the cause of failure. In the event it is determined that the
cause of the condition is the type of fuels used, repairs
may not be covered by your warranty.
Some gasolines that are not reformulated for low
emissions may contain an octane
-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask your service station operator whether or not
the fuel contains MMT. General Motors does not
recommend the use of such gasolines. If fuels containing
MMT are used, spark plug life may be reduced and your
emission control system performance may be affected.
The malfunction indicator lamp on your instrument
panel may turn on. If this occurs, return to your
authorized GM dealer for service.To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent deposits from forming in your engine and fuel
system, allowing your emission control system to
function properly. Therefore, you should not have to add
anything to the fuel. In addition, gasolines containing
oxygenates, such as ethers and ethanol, and
reformulated gasolines may be available in your area to
contribute to clean air. General Motors recommends that
you use these gasolines, particularly if they comply with
the specifications described earlier.
NOTICE:
Your vehicle was not designed for fuel that
contains methanol. Don't use it. It can corrode
metal parts in your fuel system and also damage
plastic and rubber parts. That damage wouldn't
be covered under your warranty.

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Checking Things Under the Hood
CAUTION:
Things that burn can get on hot engine parts and
start a fire. These include liquids like gasoline,
oil, coolant, brake fluid, windshield washer and
other fluids, 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.
To open the hood, first pull
the handle inside the vehicle
on the lower driver's side of
the instrument panel.Then go to the front of the vehicle and release the
secondary hood release.
Lift the hood, release the hood prop from its retainer and
put the hood prop into the slot in the hood. You may
have a lamp that comes on when you lift the hood.

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Before closing the hood, be sure all the filler caps are on
properly. Then lift the hood to relieve pressure on the
hood prop.
Remove the hood prop from the slot in the hood and
return the prop to its retainer.
Then just pull the hood down firmly to close. It will
latch when dropped from 10 to 12 inches (25 to 30 cm)
without pressing on the hood.Engine Oil
It's a good idea to check your engine oil every time you
get fuel. In order to get an accurate reading, the oil must
be warm and the vehicle must be on level ground.
The oil dipstick is a
yellow ring.
Turn off the engine and
give the oil several minutes
to drain back into the oil
pan. If you don't, the oil
dipstick might not show the
actual level.