2020 GMC TERRAIN service

GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13556230) - 2020 - CRC - 9/4/19
Driving and Operating 247
is ready to assist. LKA may assist
by gently turning the steering wheel
if the vehicle approaches a detected
lane marking.
Ais amber when
assisting. It may also provide a
Lane Departure Warning (LDW)
alert by flashing
Aamber if the
vehicle crosses a detected lane
marking. Additionally, there may be
three beeps, or the driver seat may
pulse three times, on the right or
left, depending on the lane
departure direction.
Take Steering
The LKA system does not
continuously steer the vehicle.
If LKA does not detect active driver
steering, an alert and chime may be
provided. Steer the vehicle to
dismiss. LKA may become
temporarily unavailable after
repeated take steering alerts.
When the System Does Not
Seem to Work Properly
The system performance may be
affected by:
. Close vehicles ahead.
. Sudden lighting changes, such
as when driving through tunnels.
. Banked roads.
. Roads with poor lane markings,
such as two-lane roads.
A system unavailable message may
display if the camera is blocked.
The LKA system does not need
service.
A camera blocked message may
display if the camera is blocked.
Some driver assistance systems
may have reduced performance or
not work at all. An LKA or LDW
unavailable message may display if
the systems are temporarily
unavailable. This message could be
due to a blocked camera. The LKA
system does not need service.
Clean the outside of the windshield
behind the rearview mirror. LKA assistance and/or LDW alerts
may occur due to tar marks,
shadows, cracks in the road,
temporary or construction lane
markings, or other road
imperfections. This is normal system
operation; the vehicle does not need
service. Turn LKA off if these
conditions continue.

GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13556230) - 2020 - CRC - 9/4/19
Driving and Operating 249
Recommended Fuel (LTG
- 2.0L L4 Turbo Engine)
Premium unleaded gasoline
meeting ASTM specification D4814
with a posted octane rating of 93—
(R+M)/2 —is highly recommended
for best performance and fuel
economy. Unleaded gasoline with
an octane rated as low as 87 can be
used. Using unleaded gasoline
rated below 93 octane, however, will
lead to reduced acceleration and
fuel economy. If knocking occurs,
use a gasoline rated at 93 octane
as soon as possible, otherwise, the
engine could be damaged. If heavy
knocking is heard when using
gasoline with a 93 octane rating, the
engine needs service. Do not use any fuel labeled E85 or
FlexFuel. Do not use gasoline with
ethanol levels greater than 15% by
volume.
Prohibited Fuels
(Gasoline)
Caution
Do not use fuels with any of the
following conditions; doing so
may damage the vehicle and void
its warranty:
. For vehicles that are not
FlexFuel, fuel labeled
greater than 15% ethanol by
volume, such as mid-level
ethanol blends (16–50%
ethanol), E85, or FlexFuel.
. Fuel with any amount of
methanol, methylal,
ferrocene, and aniline.
These fuels can corrode
metal fuel system parts or
damage plastic and rubber
parts.
(Continued)
Caution (Continued)
.Fuel containing metals such
as methylcyclopentadienyl
manganese tricarbonyl
(MMT), which can damage
the emissions control
system and spark plugs.
. Fuel with a posted octane
rating of less than the
recommended fuel. Using
this fuel will lower fuel
economy and performance,
and may decrease the life of
the emissions catalyst.
Fuels in Foreign
Countries
The U.S., Canada, and Mexico post
fuel octane ratings in anti-knock
index (AKI). For fuel not to use in a
foreign country, see Prohibited
Fuels (Gasoline) 0249.

GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13556230) - 2020 - CRC - 9/4/19
252 Driving and Operating
Caution
Do not use blends containing
more than 20% biodiesel. Any
engine, fuel system, or exhaust
after-treatment system damage
would not be covered by the
vehicle warranty.
As a renewable fuel, biodiesel
provides some environmental
benefits. However, biodiesel has
unique properties and needs to be
handled differently than diesel fuel.
Its use presents additional risks and
may not be appropriate in all
situations. Certain vehicle operating
modes increase these risks and
should be avoided.
Biodiesel fuel quality degrades with
time and exposure to high
temperature quicker than Ultra Low
Sulfur Diesel fuel. More frequent
refueling provides the best
opportunity to have a supply of fresh
fuel. Storage at hot ambient
temperatures will accelerate
biodiesel degradation. If the vehicle is not driven often and
uses little fuel, or if it is stored for
extended periods of time, avoid the
use of biodiesel blended fuels
above 5% by volume. When the
vehicle is stored for longer than one
month, it should be run out of
biodiesel to below one-quarter tank,
refueled with biodiesel-free fuel, and
driven several kilometers (miles)
before storage.
Cold Weather Operation
(Diesel)
In cold weather, the fuel filter may
become clogged by wax naturally
present in the fuel. To unclog it,
move the vehicle to a warm garage
area and allow the filter to warm up.
The fuel filter may need to be
replaced. See
Fuel Filter
Replacement (Diesel) 0256.
At temperatures below 0 °C (32 °F),
it is recommended to avoid using
biodiesel blends above 5% blend.
This blend may cause fuel filter
plugging, system gelling, and
freezing that may affect vehicle
starting. You may need to turn the ignition on and off a few times
before the vehicle will start. Also,
idle the vehicle for a couple of
minutes before accelerating.
It is recommended to use Ultra Low
Sulfur No. 1-D diesel fuel or a blend
of No. 1-D and No. 2-D diesel fuel to
enhance vehicle operation in cold
weather at temperatures below 0 °C
(32 °F). Use of No. 1-D diesel fuel
may lower the fuel economy. For
additional information for better cold
weather operation, see
Engine
Heater 0186.Water in Fuel (Diesel)
Improper fuel tank inspection or
cleaning, or contaminated fuel from
suppliers, can cause water to be
pumped into the fuel tank along with
the diesel fuel. If a WATER IN FUEL
- CONTACT SERVICE message
displays, the water must be drained
immediately.

GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13556230) - 2020 - CRC - 9/4/19
Driving and Operating 253
{Warning
Diesel fuel containing water is still
combustible. You or others could
be burned. If the fuel needs to be
drained, keep sparks, flames, and
smoking materials away from the
mixture.
Caution
Water in the diesel fuel can
corrode internal components of
the fuel system and lead to
severe damage. It can also
support fungus or bacteria
growth, which can damage the
fuel system and Fuel Operated
Heater (FOH), if equipped. Even
with a diesel fuel biocide, the fuel
system may still need to be
cleaned. Your dealer can advise
of the appropriate solution.(Continued)
Caution (Continued)
If the fuel tank needs to be
purged to remove water, see your
dealer or a qualified technician.
Improper purging can damage the
fuel system and block the FOH.
As an added precaution, drain the
diesel fuel filter of residual water at
every engine oil change. If the
WATER IN FUEL - CONTACT
SERVICE message comes on
frequently, even after draining water
from the fuel filter, see your dealer. Water in Fuel Troubleshooting
If the WATER IN FUEL - CONTACT
SERVICE message comes on:
Problem Recommended
Action
Message
displays but
goes off during
the ignition
cycle. The fuel filter is
partially filled
with water. Drain
the water as
soon as
possible. See
"Removing
Water from the
Fuel Filter"
following.

GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13556230) - 2020 - CRC - 9/4/19
Driving and Operating 255
FWD Shown, AWD Similar
3. Turn the drain plug counterclockwise using a
suitable tool.
4. With the engine off, press and hold ENGINE START/STOP
without applying the brake for
five seconds to place the
vehicle in Service Mode. See
Ignition Positions 0179. Wait
approximately five seconds,
and then press ENGINE
START/STOP again to turn it
off. This operation will enhance
water flow out of the filter. The filter is drained as soon as
diesel fuel emerges from
the port.
5. Retighten the drain plug by turning it clockwise.
6. Properly dispose of the water contaminated fuel.
7. Start the engine and let it run for a few minutes. During the
draining process, air may have
entered the fuel system. If the
engine stalls, the fuel system
may need to be primed. See
“Fuel Priming” following.
Fuel Priming
For the fuel system to work properly,
air cannot be in the fuel lines. If air
gets in, the engine may not start
and the fuel lines will need to be
primed before operating the vehicle.
If air is present, the following may
have happened:
. The vehicle ran out of fuel.
. The fuel filter was removed.
. The fuel lines were removed or
disconnected. .
The fuel filter water drain valve
was opened while the engine
was running.
To prime the fuel lines: 1. With the engine off, press and hold ENGINE START/STOP
without applying the brake for
five seconds to place the
vehicle in Service Mode. See
Ignition Positions 0179. Wait
approximately five seconds
and press ENGINE START/
STOP again to turn it off. Do
this step three times or more
while the engine is off.
2. Press and hold ENGINE START/STOP while applying
the brake for a maximum of
40 seconds at a time, with
five seconds between attempts,
until the engine starts. If the
engine tries to run, but does
not run smoothly, increase the
rpm’s slightly by using the
accelerator pedal. This will help
force air through the system.
3. Repeat Step 2 if the engine stalls and will not restart.

GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13556230) - 2020 - CRC - 9/4/19
260 Driving and Operating
{Warning
Overfilling the fuel tank by more
than three clicks of a standard fill
nozzle may cause:. Vehicle performance issues,
including engine stalling and
damage to the fuel system.
. Fuel spills.
. Under certain conditions,
fuel fires.
Diesel fuel can foam when filling the
tank. The automatic pump nozzle
may shut off, even if the tank is not
full. Wait for the foaming to stop,
and then fill the tank more slowly.
Be careful not to spill fuel. Wait
five seconds after pumping before
removing the fill nozzle. Clean fuel
from painted surfaces as soon as
possible. See Exterior Care0356.
Reinstall the cap by turning it
clockwise until it clicks. Push the
fuel door closed until it latches.
{Warning
If a fire starts while you are
refueling, do not remove the fill
nozzle. Shut off the flow of fuel by
shutting off the pump or by
notifying the station attendant.
Leave the area immediately.
Caution
If a new fuel cap is needed, be
sure to get the right type of cap
from your dealer. The wrong type
of fuel cap may not fit properly
and could damage the fuel
system. Accidental Refueling with
Gasoline
Caution
If the vehicle is accidentally
refueled with gasoline, do not
continue driving the vehicle
except to get to a location where
it can be stopped safely. Driving
the vehicle will damage the
engine. Tow the vehicle for
service. Have the gasoline
removed from the tank and fuel
system.
Filling a Portable Fuel
Container (Gasoline)
{Warning
Never fill a portable fuel container
while it is in the vehicle. Static
electricity discharge from the
container can ignite the fuel
vapor. You or others could be
(Continued)

GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13556230) - 2020 - CRC - 9/4/19
Driving and Operating 265
The vehicle can tow in D (Drive).
Shift the transmission to a lower
gear if the transmission shifts too
often under heavy loads and/or hilly
conditions.
When towing at higher altitudes,
engine coolant will boil at a lower
temperature than at lower altitudes.
If the engine is turned off
immediately after towing at high
altitude on steep uphill grades, the
vehicle could show signs similar to
engine overheating. To avoid this,
let the engine run, preferably on
level ground, with the transmission
in P (Park) for a few minutes before
turning the engine off. If the
overheat warning comes on, see
Engine Overheating0294.
Parking on Hills
{Warning
To prevent serious injury or death,
always park your vehicle and
trailer on a level surface when
possible. When parking your vehicle and your
trailer on a hill:
1. Press the brake pedal, but do not shift into P (Park) yet. Turn
the wheels into the curb if
facing downhill or into traffic if
facing uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, gradually release the
brake pedal to allow the chocks
to absorb the load of the trailer.
4. Reapply the brake pedal. Then apply the parking brake and
shift into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
.Start the engine.
. Shift into a gear.
. 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
The vehicle needs service more
often when used to tow trailers. See
Maintenance Schedule 0368. It is
especially important to check the
automatic transmission fluid, engine
oil, axle lubricant, belts, cooling
system, and brake system before
and during each trip.
Check periodically that all nuts and
bolts on the trailer hitch are tight.
Engine Cooling When Trailer
Towing
The cooling system may temporarily
overheat during severe operating
conditions. See Engine Overheating
0 294.

GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13556230) - 2020 - CRC - 9/4/19
Driving and Operating 271
Trailer Lamps
Always check all trailer lamps are
working at the beginning of each
trip, and periodically on longer trips.
Turn Signals When Towing a
Trailer
When properly connected, the trailer
turn signals will illuminate to indicate
the vehicle is turning, changing
lanes, or stopping. When towing a
trailer, the arrows on the instrument
cluster will illuminate even if the
trailer is not properly connected or
the bulbs are burned out.
Trailer Tires
Special Trailer (ST) tires differ from
vehicle tires. Trailer tires are
designed with stiff sidewalls to help
prevent sway and to support heavy
loads. These features can make it
difficult to determine if the trailer tire
pressures are low only based on a
visual inspection.Always check all trailer tire
pressures before each trip when the
tires are cool. Low trailer tire
pressure is a leading cause of trailer
tire blow-outs.
Trailer tires deteriorate over time.
The trailer tire sidewall will show the
week and year the tire was
manufactured. Many trailer tire
manufacturers recommend
replacing tires more than six
years old.
Overloading is another leading
cause of trailer tire blow-outs. Never
load your trailer with more weight
than the tires are designed to
support. The load rating is located
on the trailer tire sidewall.
Always know the maximum speed
rating for the trailer tires before
driving. This may be significantly
lower than the vehicle tire speed
rating. The speed rating may be on
the trailer tire sidewall. If the speed
rating is not shown, the default
trailer tire speed rating is 105 km/h
(65 mph).
Conversions and
Add-Ons
Add-On Electrical
Equipment
{Warning
The Data Link Connector (DLC) is
used for vehicle service and
Emission Inspection/Maintenance
testing. See
Malfunction Indicator
Lamp (Check Engine Light) 0115.
A device connected to the DLC —
such as an aftermarket fleet or
driver-behavior tracking device —
may interfere with vehicle
systems. This could affect vehicle
operation and cause a crash.
Such devices may also access
information stored in the vehicle’s
systems.