2008 GMC CANYON ECU

Four-Wheel-Drive Vehicles
Use the following procedure to dolly tow your vehicle
from the front:
1. Drive the vehicle onto the dolly.
2. Firmly set the parking brake. SeeParking Brake on
page 2-32for more information.
3. Put an automatic transmission in PARK (P) or a
manual transmission in FIRST (1).
4. Follow the dolly manufacturer’s instructions to attach
and secure the vehicle being towed to the dolly and
then the loaded dolly to the tow vehicle.
{CAUTION:
Shifting a four-wheel-drive vehicle’s transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in PARK (P) for
an automatic transmission, or if your vehicle is
in gear, for a manual transmission. You or
others could be injured. Make sure the parking
brake is rmly set before you shift the transfer
case to NEUTRAL.
5. Shift the transfer case to NEUTRAL. See
Four-Wheel Drive on page 2-28for more
information.
6. Release the parking brake only after the vehicle
being towed is rmly attached to the tow vehicle.
7. Turn the ignition to LOCK.
If the tow vehicle will not be started or driven for
six weeks or more, remove the battery cable
from the negative terminal (post) of the battery to
prevent your battery from draining while towing.
After towing see “Shifting Out of NEUTRAL” under
Four-Wheel Drive on page 2-28.
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Rear Towing (Rear Wheels Off the Ground)
Two-Wheel-Drive Vehicles
Use the following procedure to tow your vehicle from
the rear:
1. Drive the vehicle onto the dolly.
2. Firmly set the parking brake. SeeParking Brake on
page 2-32for more information.3. Put an automatic transmission in PARK (P) or a
manual transmission in FIRST (1).
4. Follow the dolly manufacturer’s instructions to
attach and secure the vehicle being towed to
the dolly and then the loaded dolly to the tow
vehicle. Make sure the wheels are straight before
towing.
For manual transmission vehicles, make sure the
wheels are straight before proceeding to the
next steps. On automatic transmission vehicles, use
an adequate clamping device to ensure that the
front wheels are locked into the straight position.
5. Release the parking brake only after the vehicle
being towed is rmly attached to the tow vehicle.
6. Turn the ignition to LOCK.
If the tow vehicle will not be started or driven for
six weeks or more, remove the battery cable
from the negative terminal (post) of the battery to
prevent your battery from draining while towing.
4-42

Four-Wheel-Drive Vehicles
Use the following procedure to tow your vehicle from
the rear:
1. Drive the vehicle onto the dolly.
2. Firmly set the parking brake. SeeParking Brake on
page 2-32for more information.
3. Put an automatic transmission in PARK (P) or a
manual transmission in FIRST (1).
4. Follow the dolly manufacturer’s instructions to
attach and secure the vehicle being towed to the
dolly and then the loaded dolly to the tow vehicle.
For manual transmission vehicles, make sure the
wheels are straight before proceeding to the nextsteps. On automatic transmission vehicles, use an
adequate clamping device to ensure that the front
wheels are locked into the straight position.
{CAUTION:
Shifting a four-wheel-drive vehicle’s transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in PARK (P) for
an automatic transmission, or if your vehicle is
in gear, for a manual transmission. You or
others could be injured. Make sure the parking
brake is rmly set before you shift the transfer
case to NEUTRAL.
5. Shift the transfer case to NEUTRAL. See
Four-Wheel Drive on page 2-28for more
information.
6. Release the parking brake only after the vehicle
being towed is rmly attached to the tow vehicle.
7. Turn the ignition to LOCK.
If the tow vehicle will not be started or driven for
six weeks or more, remove the battery cable
from the negative terminal (post) of the battery to
prevent your battery from draining while towing.
After towing, see “Shifting Out of NEUTRAL” under
Four-Wheel Drive on page 2-28.
4-43

4WD Extended Cab Axle Ratio Maximum Trailer Weight GCWR*
Manual Transmission,
2.9L Engine3.73 1,900 lbs (861 kg) 6,000 lbs (2 722 kg)
Manual Transmission,
2.9L Engine4.10 1,900 lbs (861 kg) 6,000 lbs (2 722 kg)
*The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be
exceeded.
4WD Crew Cab Axle Ratio Maximum Trailer Weight GCWR*
Automatic Transmission,
3.7L Engine3.73 5,500 lbs (2 495 kg) 9,800 lbs (4 445 kg)
Automatic Transmission,
5.3L Engine3.42 6,000 lbs (2 722 kg) 10,400 lbs (4 717 kg)
*The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be
exceeded.
Ask your dealer/retailer for our trailering information or advice, or you can write us at our Customer Assistance
Offices. SeeCustomer Assistance Offices on page 7-5for more information.
4-49

Trailer Brakes
If your trailer weighs more than 1,000 lbs (450 kg)
loaded, then it needs its own brakes — and they must
be adequate. Be sure to read and follow the instructions
for the trailer brakes so you’ll be able to install, adjust
and maintain them properly.
Your trailer’s brake system can tap into the vehicle’s
hydraulic brake system only if:
The trailer parts can withstand 3,000 psi
(20 650 kPa) of pressure.
The trailer’s brake system will use less than
0.02 cubic inch (0.3 cc) of uid from your vehicle’s
master cylinder. Otherwise, both braking systems
won’t work well. You could even lose your brakes.
If everything checks out this far, then make the brake
uid tap at the port on the master cylinder that sends
uid to the rear brakes. But don’t use copper tubing for
this. If you do, it will bend and nally break off. Use steel
brake tubing.
Driving with a Trailer
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.
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Radiator Pressure Cap
Notice:If the pressure cap is not tightly installed,
coolant loss and possible engine damage may occur.
Be sure the cap is properly and tightly secured.
SeeEngine Compartment Overview on page 5-12for
more information on location.
Engine Overheating
A coolant temperature gage is on the instrument panel.
SeeEngine Coolant Temperature Gage on page 3-33.
The air conditioning might stop working if the engine
is too hot. This is normal and helps cool the engine.
If Steam Is Coming From Your Engine
{CAUTION:
Steam from an overheated engine can burn
you badly, even if you just open the hood.
Stay away from the engine if you see or hear
steam coming from it. Just turn it off and
get everyone away from the vehicle until it
cools down. Wait until there is no sign of
steam or coolant before you open the hood.
If you keep driving when your engine is
overheated, the liquids in it can catch re.
You or others could be badly burned. Stop
your engine if it overheats, and get out of
the vehicle until the engine is cool.
Notice:If your engine catches re because you
keep driving with no coolant, your vehicle can
be badly damaged. The costly repairs would
not be covered by your warranty.
5-29

4. Fill the coolant recovery tank to the
FULL COLD mark.
5. Reinstall the cap on the coolant recovery tank,
but leave the radiator pressure cap off.6. Start the engine and let it run until you can feel
the upper radiator hose getting hot. Watch out
for the engine cooling fan.
7. By this time, the coolant level inside the radiator
ller neck might be lower. If the level is lower, add
more of the proper DEX-COOL
®coolant mixture
through the ller neck until the level reaches
the base of the ller neck.
8. Then replace the pressure cap.
At any time during this procedure if coolant begins to
ow out of the ller neck, reinstall the pressure cap.
Be sure to secure it tightly.
5-35

Headlamps
A. Low-Beam Headlamp/Daytime Running Lamps (DRL)
B. High-Beam Headlamp
To replace one of these bulbs:
1. Open the hood. SeeHood Release on page 5-11
for more information.
2. Reach in and access the bulb sockets from inside
the engine compartment.3. Turn the bulb socket counterclockwise to remove it
from the headlamp assembly and pull it straight out.
4. Unplug the electrical connector from the old bulb
by releasing the clips on the bulb socket.
5. Replace with a new bulb socket.
6. Plug in the electrical connector to the new bulb
socket.
7. Reinstall the new bulb socket into the headlamp
assembly and turn it clockwise to secure.
8. Close the hood.
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