2007 GMC SAVANA check engine

Hill and Mountain Roads
Driving on steep hills or mountains is different
from driving in flat 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.
•Keep your vehicle in good shape. Check
all fluid 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, your 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 your engine assist
your brakes on a steep downhill slope.
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{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/or the fuel operated
heater exhaust system, if equipped. And
check around again from time to time to be
sure snow does not collect there. If your
vehicle has a diesel engine and a fuel
operated heater, see “Fuel Operated Heater
(FOH)” in the diesel engine supplement.
Open a window just a little on the side of
the vehicle that is away from the wind.
This will help keep CO out.Run your engine only as long as you must.
This saves fuel. When you run the engine, make it
go a little faster than just idle. That is, push the
accelerator slightly. This uses less fuel for the heat
that you get and it keeps the battery (or batteries)
charged. You will need a well-charged battery
(or batteries) to restart the vehicle, and possibly for
signaling later on with your headlamps. Let the
heater run for a while.
Then, shut the engine off and close the window
almost all the way to preserve the heat. Start
the engine again and repeat this only when you
feel really uncomfortable from the cold. But do it as
little as possible. Preserve the fuel as long as
you can. To help keep warm, you can get out of
the vehicle and do some fairly vigorous exercises
every half hour or so until help comes.
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Driving with a Trailer
{CAUTION:
If you have a rear-most window open and
you pull a trailer with your vehicle, carbon
monoxide (CO) could come into your
vehicle. You can not see or smell CO. It can
cause unconsciousness or death. See
Engine Exhaust on page 132. To maximize
your safety when towing a trailer:
Have your exhaust system inspected
for leaks, and make necessary repairs
before starting on your trip.
Keep the rear-most windows closed.
If exhaust does come into your vehicle
through a window in the rear or another
opening, drive with your front, main
heating or cooling system on and with
the fan on any speed. This will bring
fresh, outside air into your vehicle.
CAUTION: (Continued)
CAUTION: (Continued)
Do not use the climate control setting for
maximum air because it only recirculates
the air inside your vehicle. See Climate
Control System in the Index.
Towing a trailer requires a certain amount of
experience. Before setting out for the open road,
you’ll want to get to know your rig. Acquaint yourself
with the feel of handling and braking with the added
weight of the trailer. And always keep in mind that
the vehicle you are driving is now a good deal
longer and not nearly as responsive as your vehicle
is by itself.
Before you start, check all trailer hitch parts and
attachments, safety chains, electrical connector,
lamps, tires and mirror adjustment. If the trailer has
electric brakes, start your vehicle and trailer moving
and then apply the trailer brake controller by hand
to be sure the brakes are working. This lets you
check your electrical connection at the same time.
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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 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 a lower gear
under heavy loads and/or hilly conditions.
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) for a few minutes before turning the
engine off. If you do get the overheat warning, see
Engine Overheating on page 309.
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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.
Trailer Wiring Harness
The optional heavy-duty trailer wiring package
includes a seven-wire harness assembly at
the rear of the vehicle and a four-wire
harness assembly under the left hand side
of the instrument panel. The seven-wire
harness assembly is taped together and
located in a frame pocket at the driver side
rear left corner of the frame.The seven-wire harness includes a 30-amp feed
wire. Both harnesses come without connectors and
should be wired by a qualified electrical technician.
The technician can use the following color code
chart when connecting the wiring harness to
your trailer and trailer brake controller.
Seven-Wire Harness
•Light Green: Back-up lamps
•Brown: Parking lamps
•Yellow: Left stoplamp and turn signal
•Dark Green: Right stoplamp and turn signal
•Dark Blue: Use for electric trailer brakes
•Red/Black Stripe: Trailer accessory
•White (heavy gage): Ground wire
Four-Wire Harness (Trailer Brake Controller)
•Black: Ground
•Red/White Stripe: Fused Battery
•Dark Blue: Trailer Brake Feed
•Light Blue: Fused Stoplamp/CHMSL
282

Service........................................................ 286
Accessories and Modifications................... 286
California Proposition 65 Warning.............. 286
Doing Your Own Service Work.................. 287
Adding Equipment to the Outside
of Your Vehicle...................................... 287
Fuel............................................................. 288
Gasoline Octane........................................ 288
Gasoline Specifications.............................. 288
California Fuel........................................... 289
Additives................................................... 289
Fuel E85 (85% Ethanol)............................ 290
Fuels in Foreign Countries........................ 291
Filling the Tank......................................... 292
Filling a Portable Fuel Container............... 294
Checking Things Under the Hood.............. 294
Hood Release........................................... 295
Engine Compartment Overview.................. 296
Engine Oil (Gasoline Engine).................... 297Engine Oil Life System
(Gasoline Engine).................................. 300
Engine Air Cleaner/Filter............................ 302
Automatic Transmission Fluid.................... 303
Engine Coolant.......................................... 306
Radiator Pressure Cap.............................. 309
Engine Overheating................................... 309
Cooling System......................................... 311
Engine Fan Noise..................................... 317
Power Steering Fluid ................................. 317
Windshield Washer Fluid........................... 318
Brakes...................................................... 319
Battery...................................................... 323
Jump Starting............................................ 324
All-Wheel Drive........................................... 330
Rear Axle.................................................... 331
Front Axle................................................... 331
Section 5 Service and Appearance Care
283

California Fuel
If your vehicle is certified to meet California
Emissions Standards, it is designed to operate on
fuels that meet California specifications. 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 specifications, 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 178. 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.
Additives
To provide cleaner air, all gasolines in the United
States are now required to contain additives
that will help prevent engine and fuel system
deposits from forming, allowing your emission
control system to work properly. In most cases,
you should not have to add anything to your fuel.However, some gasolines contain only the
minimum amount of additive required to meet U.S.
Environmental Protection Agency regulations.
To help keep fuel injectors and intake valves clean,
or if your vehicle experiences problems due to
dirty injectors or valves, look for gasoline that is
advertised as TOP TIER Detergent Gasoline. Also,
your dealer has additives that will help correct
and prevent most deposit-related problems.
Gasolines containing oxygenates, such as ethers
and ethanol, and reformulated gasolines may
be available in your area. General Motors
recommends that you use these gasolines if they
comply with the specifications described earlier.
However, E85 (85% ethanol) and other fuels
containing more than 10% ethanol must not be
used in vehicles that were not designed for
those fuels.
Notice:Your vehicle was not designed for
fuel that contains methanol. Do not use
fuel containing methanol. It can corrode metal
parts in your fuel system and also damage
the plastic and rubber parts. That damage
would not be covered under your warranty.
289

Some gasolines that are not reformulated for low
emissions may contain an octane-enhancing
additive called methylcyclopentadienyl manganese
tricarbonyl (MMT); ask the attendant where you
buy gasoline whether the fuel contains MMT.
General Motors recommends against the use of
such gasolines. Fuels containing MMT can reduce
the life of spark plugs and the performance of
the emission control system may be affected. The
malfunction indicator lamp may turn on. If this
occurs, return to your dealer for service.
Fuel E85 (85% Ethanol)
The 8th digit of your Vehicle Identification Number
(VIN) shows the code letter or number that
identifies your engine. You will find the VIN at the
top left of the instrument panel. SeeVehicle
Identication Number (VIN) on page 386.
If your vehicle has the 5.3L V8 engine
(VIN Code Z only), you may use either regular
unleaded gasoline or ethanol fuel containing up to
85% ethanol (E85); also seeFuel on page 288.
In all other engines, use only the unleaded
gasoline described underGasoline Octane on
page 288.Only vehicles that have the 5.3L V8 engine
(VIN Code Z) may use 85% ethanol fuel (E85).
General Motors encourages the use of E85
in vehicles that are designed to use it. The ethanol
in E85 is a “renewable” fuel, meaning it is made
from renewable sources such as corn and
other crops.
Many service stations will not have an
85% ethanol fuel (E85) pump available.
The U. S. Department of Energy has an
alternative fuels website (www.eere.energy.gov/
afdc/infrastructure/locator.html) that can help
you find E85 fuel. Those stations that do have
E85 should have a label indicating ethanol content.
Do not use the fuel if the ethanol content is
greater than 85%.
At a minimum, E85 should meet ASTM
Specification D 5798. By definition, this means
that fuel labeled E85 will have an ethanol content
between 70% and 85%. Filling the fuel tank
with fuel mixtures that do not meet ASTM
specifications can affect driveability and could
cause the check engine light to come on.
290