2008 GMC SAVANA check engine

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. SeeEngine Exhaust on page 2-30.
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. 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.
During your trip, check occasionally to be sure that the
load is secure, and that the lamps and any trailer
brakes are still working.
Following Distance
Stay at least twice as far behind the vehicle ahead as
you would when driving your vehicle without a trailer.
This can help you avoid situations that require
heavy braking and sudden turns.
4-38

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 wiring harness, with a seven-pin connector at the
rear of the vehicle and a four-wire harness assembly
under the driver side of the instrument panel. The
four-wire harness assembly comes without a connector.
If your vehicle does not have a trailer hitch, the
seven-wire harness assembly with connector is taped
together and located in a frame pocket at the driver side
rear left corner of the frame.
If your vehicle has a trailer hitch, the seven-wire
harness assembly with connector is attached to a
bracket on the hitch platform. In both cases, the
seven-wire harness has a connector and includes a
30-amp feed wire.
4-41

Service............................................................5-3
Accessories and Modifications..........................5-3
California Proposition 65 Warning.....................5-3
California Perchlorate Materials Requirements.....5-4
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside of
Your Vehicle..............................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-6
Gasoline Specifications....................................5-6
California Fuel...............................................5-6
Additives.......................................................5-7
Fuel E85 (85% Ethanol)..................................5-8
Fuels in Foreign Countries...............................5-9
Filling the Tank............................................5-10
Filling a Portable Fuel Container.....................5-12
Checking Things Under the Hood....................5-12
Hood Release..............................................5-13
Engine Compartment Overview.......................5-14
Engine Oil (Gasoline Engine)..........................5-15
Engine Oil Life System..................................5-18
Engine Air Cleaner/Filter................................5-19
Automatic Transmission Fluid.........................5-20
Engine Coolant.............................................5-23
Radiator Pressure Cap..................................5-26Engine Overheating.......................................5-26
Cooling System............................................5-28
Engine Fan Noise.........................................5-34
Power Steering Fluid.....................................5-34
Windshield Washer Fluid................................5-35
Brakes........................................................5-36
Battery........................................................5-39
Jump Starting...............................................5-40
All-Wheel Drive..............................................5-44
Rear Axle.......................................................5-45
Front Axle......................................................5-45
Noise Control System.....................................5-46
Tampering with Noise Control System
Prohibited.................................................5-46
Bulb Replacement..........................................5-48
Halogen Bulbs..............................................5-48
Headlamps..................................................5-48
Front Turn Signal, Sidemarker and
Parking Lamps..........................................5-50
Center High-Mounted Stoplamp (CHMSL).........5-50
Taillamps.....................................................5-51
Replacement Bulbs.......................................5-52
Windshield Wiper Blade Replacement..............5-52
Section 5 Service and Appearance Care
5-1

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 can cause wind noise
and can affect fuel economy and windshield washer
performance. Check with your dealer/retailer before
adding equipment to the outside of your vehicle.
Fuel
If your vehicle has a diesel engine, see “Diesel Fuel
Requirements and Fuel System” in the DURAMAX®
Diesel manual.
For vehicles with gasoline engines, please read this.
Gasoline
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, we recommend the use of gasoline
advertised as TOP TIER Detergent Gasoline.
The 8th digit of the Vehicle Identification Number (VIN)
shows the code letter or number that identifies your
vehicle’s engine. The VIN is at the top left of the
instrument panel. SeeVehicle Identification
Number (VIN) on page 5-103.
If your vehicle has the 5.3L V8 engine (VIN Code 4),
you can use either regular unleaded gasoline or ethanol
fuel containing up to 85% ethanol (E85); also see
Fuel E85 (85% Ethanol) on page 5-8. In all other
gasoline engines, use only regular unleaded gasoline.
5-5

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 specification
D 4814 in the United States or CAN/CGSB-3.5 or
3.511 in Canada. Some gasolines contain an
octane-enhancing additive called methylcyclopentadienyl
manganese tricarbonyl (MMT). We recommend against
the use of gasolines containing MMT. SeeAdditives on
page 5-7for additional information.
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 might be affected.
The malfunction indicator lamp could turn on and your
vehicle might fail a smog-check test. SeeMalfunction
Indicator Lamp on page 3-36. If this occurs, return to your
authorized dealer/retailer for diagnosis. If it is determined
that the condition is caused by the type of fuel used,
repairs might not be covered by your warranty.
5-6

Filling a Portable Fuel Container
{CAUTION:
Never ll a portable fuel container while it is in
your vehicle. Static electricity discharge from
the container can ignite the fuel vapor. You
can be badly burned and your vehicle damaged
if this occurs. To help avoid injury to you and
others:
Dispense fuel only into approved
containers.
Do not ll a container while it is inside a
vehicle, in a vehicle’s trunk, pickup bed, or
on any surface other than the ground.
Bring the ll nozzle in contact with the
inside of the ll opening before operating
the nozzle. Contact should be maintained
until the lling is complete.
Do not smoke while pumping fuel.
Do not use a cellular phone while
pumping fuel.
Checking Things Under
the Hood
{CAUTION:
Things that burn can get on hot engine or fuel
operated heater (FOH) 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 or fuel operated
heater (FOH).
5-12

A. Battery. SeeBattery on page 5-39.
B. Radiator Pressure Cap. SeeRadiator Pressure Cap
on page 5-26.
C. Coolant Recovery Tank. SeeCooling System on
page 5-28.
D. Automatic Transmission Fluid Dipstick. See
“Checking the Fluid Level” underAutomatic
Transmission Fluid on page 5-20.
E. Engine Oil Fill Cap. See “When to Add Engine Oil”
underEngine Oil (Gasoline Engine) on page 5-15.
F. Engine Oil Dipstick. See “Checking Engine Oil” under
Engine Oil (Gasoline Engine) on page 5-15.
G. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-19.
H. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 5-34.
I. Brake Master Cylinder Reservoir. See “Brake Fluid”
underBrakes on page 5-36.
J. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on page 5-35.Engine Oil (Gasoline Engine)
If your vehicle has a diesel engine, see “Engine Oil” in
the DURAMAX®Diesel manual.
Checking Engine Oil
It is a good idea to check the 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 engine oil dipstick handle is a yellow loop. See
Engine Compartment Overview on page 5-14for the
location of the engine oil dipstick.
1. Turn off the engine and give the oil several minutes
to drain back into the oil pan. If you do not do this,
the oil dipstick might not show the actual level.
2. Pull out the dipstick and clean it with a paper towel
or cloth, then push it back in all the way. Remove it
again, keeping the tip down, and check the level.
5-15

Engine Oil Additives
Do not add anything to the oil. The recommended
oils with the starburst symbol that meet
GM Standard GM6094M are all you need for good
performance and engine protection.
Engine Oil Life System
When to Change Engine Oil
Your vehicle has a computer system that lets you know
when to change the engine oil and filter. This is based
on engine revolutions and engine temperature, and not
on mileage. Based on driving conditions, the mileage
at which an oil change will be indicated can vary
considerably. For the oil life system to work properly, you
must reset the system every time the oil is changed.
When the system has calculated that oil life has been
diminished, it will indicate that an oil change is
necessary. A CHANGE ENGINE OIL SOON message
will come on. SeeDIC Warnings and Messages on
page 3-49. Change the oil as soon as possible within the
next 600 miles (1 000 km). It is possible that, if you are
driving under the best conditions, the oil life system might
not indicate that an oil change is necessary for over
a year. However, the engine oil and filter must be
changed at least once a year and at this time the system
must be reset. Your dealer/retailer has trained servicepeople who will perform this work using genuine parts
and reset the system. It is also important to check the oil
regularly and keep it at the proper level.
If the system is ever reset accidentally, you must
change the oil at 3,000 miles (5 000 km) since your last
oil change. Remember to reset the oil life system
whenever the oil is changed.
How to Reset the Engine Oil Life
System
The Engine Oil Life System calculates when to change
the engine oil and filter based on vehicle use. Whenever
the oil is changed, reset the system so it can calculate
when the next oil change is required. If a situation occurs
where you change the oil prior to a CHANGE ENGINE
OIL SOON message being turned on, reset the system.
To reset the CHANGE ENGINE OIL SOON message:
1. Turn the ignition key to ON/RUN with the engine off.
2. Fully press and release the accelerator pedal slowly
three times within five seconds.
3. Turn the key to LOCK/OFF.
If the message comes back on when you start your
vehicle, the engine oil life system has not reset. Repeat
the procedure. If it still does not reset, see your
dealer/retailer for service.
5-18