2009 GMC YUKON HYBRID check engine

Tachometer
When the gas engine is off and the key is in the
ON/RUN position, the position of the tachometer
indicator shows the state of the vehicle:
•AUTO STOP position indicates that the vehicle is
still able to move and the engine could restart,
by an Auto Start, at any time.
•OFF position indicates that the engine is off.
When the engine is on, the tachometer indicator shows
the engine’s revolutions per minute (rpm).
Charging System Light
This light will come on
briefly when the
ignition is turned to
ACC/ACCESSORY or
ON/RUN, but the engine is
not running, as a check
to show it is working.
It should go out once the engine has been started. If it
stays on, or comes on while driving, there could be
a problem with the charging system. A charging system
Driver Information Center (DIC) message may also
appear. SeeDIC Warnings and Messages on page 3-12
for more information. This light could indicate that
there are electrical problems. Have it checked right
away. If a short distance must be driven with the light
on, be certain to turn off all the accessories, such as the
radio and air conditioner. United States Version
shown, Canada similar
3-4

A reading in the low pressure zone may be caused by
a dangerously low oil level or some other problem
causing low oil pressure. Check the oil as soon
as possible.
{CAUTION:
Do not keep driving if the oil pressure is low.
The engine can become so hot that it catches fire.
Someone could be burned. Check the oil as soon
as possible and have the vehicle serviced.
Notice:Lack of proper engine oil maintenance can
damage the engine. The repairs would not be
covered by the vehicle warranty. Always follow the
maintenance schedule in this manual for changing
engine oil.
AUTO STOP
When the engine goes into Automatic Engine Stop, the
oil pressure gage drops to zero when the tachometer
is at the AUTO STOP position. This is normal and
oil pressure returns to the normal operating range once
the engine starts.
SeeStarting the Vehicle on page 2-3for more
information.
AUTO STOP displays in the Driver Information
Center (DIC) when the vehicle speed is zero.
SeeDIC Warnings and Messages on page 3-12
for more information.
3-9

Oil Pressure Light
{CAUTION:
Do not keep driving if the oil pressure is low.
The engine can become so hot that it catches fire.
Someone could be burned. Check the oil as soon
as possible and have the vehicle serviced.
Notice:Lack of proper engine oil maintenance can
damage the engine. The repairs would not be
covered by the vehicle warranty. Always follow the
maintenance schedule in this manual for changing
engine oil.This light comes on briefly
as a check it works, when
the ignition is in ON/RUN.
If it does not, have the
vehicle serviced.
If the light comes on and stays on, it means that oil is
not flowing through the engine properly. The vehicle
could be low on oil and might have some other system
problem.
During an AUTO STOP there is zero oil pressure, but
this light will not come on.
3-10

SERVICE BATTERY CHARGING
SYSTEM
If the hybrid battery system faults or fails this message
will appear on the DIC. The engine auto stop feature
will be disabled and the battery/charging system light will
appear in the instrument panel cluster. See “Battery
Warning Light” in the owner manual Index.
Driving with this light on could drain your batteries.
Have the electrical system checked as soon as possible.
Pressing the select button or the trip odometer reset
stem on the instrument panel cluster will acknowledge
this message and clear it from the DIC display.
HOOD OPEN
If the hood is not fully closed or there is a problem
with the hood switch, this message will be displayed.
Close the hood to clear the message. If the HOOD
OPEN message continues to be displayed after
verifying the hood is closed, you should have the hood
switch serviced. Pressing the select button or the
trip odometer reset stem on the instrument panel cluster
will acknowledge this message and clear it from the
DIC display.
When this message is displayed, the auto stop
function will not operate. If the vehicle is in auto stop
mode when this message appears, the engine will
instantly start.
OIL PRESSURE LOW STOP ENGINE
If engine oil pressure is low, this message will be
displayed on the DIC. Stop the vehicle as soon as safely
possible and do not operate it until the cause of the
low oil pressure has been corrected. Check your oil level
as soon as possible and have your vehicle serviced.
See “Engine Oil” in the owner manual Index.
SERVICE BRAKE SYSTEM
This message will be displayed if there is a problem
with the brake system. You will still be able to brake, but
it will be noticeably more difficult. Pull off the road to a
safe location and have your vehicle towed to the nearest
dealer/retailer for service. See “Brakes,” “Brake System
Warning Light,” and “ABS Brake System Warning
Light” in the owner manual Index.
SERVICE HYBRID SYSTEM
If this message is displayed on the DIC, the vehicle may
continue to operate, but you need to have it serviced
as soon as possible.
SERVICE POWER STEERING
This message displays if a problem has been detected
with the electric power steering. Have your vehicle
serviced by your dealer/retailer immediately.
3-13

Service............................................................5-2
Doing Your Own Service Work.........................5-2
Checking Things Under the Hood.....................5-3
High Voltage Devices and Wiring......................5-3
Engine Compartment Overview.........................5-4
Automatic Transmission Fluid...........................5-5
Drive Motor/Generator Control Module (DMCM)
Coolant Surge Tank Pressure Cap..................5-6
Drive Motor/Generator Control Module (DMCM)
Cooling System...........................................5-6
Power Steering Fluid.....................................5-11
Brakes........................................................5-11
Battery........................................................5-15
Jump Starting...............................................5-16
Bulb Replacement..........................................5-21
Taillamps, Turn Signal, Stoplamps and
Back-up Lamps.........................................5-21
Replacement Bulbs.......................................5-22Electrical System............................................5-22
Fuses and Circuit Breakers............................5-22
Underhood Fuse Block..................................5-22
Tires..............................................................5-24
Inflation - Tire Pressure.................................5-24
Tire Pressure Monitor Operation.....................5-25
Tire Inspection and Rotation...........................5-29
Tire Chains..................................................5-30
If a Tire Goes Flat........................................5-30
Tire Sealant and Compressor Kit
(Without Selector Switch)............................5-32
Tire Sealant and Compressor Kit
(With Selector Switch)................................5-42
Tire Sealant and Compressor Kit Storage.........5-50
Capacities and Specications..........................5-52
Section 5 Service and Appearance Care
5-1

A. See “Engine Air Cleaner/Filter” in the owner manual.
B. Drive Motor/Generator Control Module (DMCM).
SeeDrive Motor/Generator Control Module (DMCM)
Cooling System on page 5-6.
C. Engine Oil Dipstick. See “Engine Oil” in the owner
manual.
D. Automatic Transmission Fluid Dipstick. See
Automatic Transmission Fluid on page 5-5.
E. Brake Fluid Reservoir. SeeBrakes on page 5-11.
F. See “Underhood Fuse Block” in the owner manual.
G. See “Windshield Washer Fluid” in the owner
manual.
H. Hybrid Auxiliary Fuse Block. SeeUnderhood Fuse
Block on page 5-22.
I. DMCM Coolant Surge Tank Pressure Cap. See
Drive Motor/Generator Control Module (DMCM)
Coolant Surge Tank Pressure Cap on page 5-6.
J. See “Coolant Surge Tank Pressure Cap” in
the owner manual.
K. Engine Oil Fill Cap. See “Engine Oil” in the owner
manual.Automatic Transmission Fluid
For more information, see “Automatic Transmission
Fluid” in the owner manual Index.
Checking the Fluid Level
Your vehicle’s automatic transmission dipstick looks like
this. For more information on location, seeEngine
Compartment Overview on page 5-4.
5-5

Power Steering Fluid
The vehicle has electric power steering and does not
use power steering fluid.
Brakes
Brake Fluid
The brake master cylinder
reservoir is filled with
DOT-3 brake fluid. See
Engine Compartment
Overview on page 5-4
for the location of
the reservoir.
There are only two reasons why the brake fluid level in
the reservoir might go down:
•The brake fluid level goes down because of normal
brake lining wear. When new linings are installed,
the fluid level goes back up.
•A fluid leak in the brake hydraulic system can also
cause a low fluid level. Have the brake hydraulic
system fixed, since a leak means that sooner
or later the brakes will not work well.Do not top off the brake fluid. Adding fluid does not
correct a leak. If fluid is added when the linings
are worn, there will be too much fluid when new brake
linings are installed. Add or remove brake fluid, as
necessary, only when work is done on the brake
hydraulic system.
{CAUTION:
If too much brake fluid is added, it can spill on
the engine and burn, if the engine is hot enough.
You or others could be burned, and the vehicle
could be damaged. Add brake fluid only when
work is done on the brake hydraulic system.
See “Checking Brake Fluid” in this section.
When the brake fluid falls to a low level, the brake
warning light comes on. See “Brake System Warning
Light” in the owner manual.
Refer to the Maintenance Schedule to determine when
to check the brake fluid. See “Scheduled Maintenance”
in the owner manual.
5-11

Checking Brake Fluid
Check brake fluid by looking at the brake fluid reservoir.
SeeEngine Compartment Overview on page 5-4.
With the engine not running for at least one minute, the
maximum fluid level (A) is at the top of the reservoir
body. With the engine running, the fluid level should be
in the proper operating range (B) between the MIN
and MAX marks. If it is not, have the brake hydraulic
system checked to see if there is a leak.After work is done on the brake hydraulic system,
make sure the level, with the engine running, is in
the proper operating range (B) between the MIN and
MAX marks.
What to Add
Use only new DOT-3 brake fluid from a sealed
container. See “Recommended Fluids and Lubricants”
in the owner manual.
Always clean the brake fluid reservoir cap and the area
around the cap before removing it. This helps keep
dirt from entering the reservoir.
{CAUTION:
With the wrong kind of fluid in the brake hydraulic
system, the brakes might not work well. This could
cause a crash. Always use the proper brake fluid.
5-12