2010 GMC YUKON HYBRID engine

Engine Compartment Overview
When you open the hood on your vehicle, you will see:
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A. See“Engine Air Cleaner/Filter” in the owner
manual.
B. Drive Motor/Generator Control Module (DMCM). See Drive Motor/Generator Control Module
(DMCM) Cooling System on page 6‑9.
C. Engine Oil Dipstick. See “Engine Oil”in the owner
manual.
D. Automatic Transmission Fluid Dipstick. See Automatic Transmission Fluid on page 6‑5.
E. Brake Fluid Reservoir. See Brakes on page 6‑13.
F. See “Underhood Fuse Block” in the owner manual.
G. See “Windshield Washer Fluid” in the owner
manual.
H. Hybrid Auxiliary Fuse Block. See Underhood Fuse
Block on page 6‑26.
I. DMCM Coolant Surge Tank Pressure Cap. See Drive Motor/Generator Control Module (DMCM)
Coolant Surge Tank Pressure Cap on page 6‑8.
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
When to Check and Change Automatic
Transmission Fluid
It is usually not necessary to check the transmission
fluid level. The only reason for fluid loss is a
transmission leak or overheating the transmission.
If you suspect a small leak, then use the following
checking procedures to check the fluid level. However,
if there is a large leak, then it may be necessary to have
the vehicle towed to a dealer/retailer service department
and have it repaired before driving the vehicle further.
Notice: Use of the incorrect automatic transmission
fluid may damage the vehicle, and the damages may
not be covered by the vehicle's warranty. Always
use the automatic transmission fluid listed in
Recommended Fluids and Lubricants on page 7‑2.
Change the fluid and filter at the intervals listed in the
Maintenance Schedule. See Scheduled Maintenance in
the owner manual. Be sure to use the transmission fluid
listed in Recommended Fluids and Lubricants
on
page 7‑2.
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How to Check Automatic Transmission
Fluid
Notice:Too much or too little fluid can damage your
transmission. Too much can mean that some of the
fluid could come out and fall on hot engine parts or
exhaust system parts, starting a fire. Too little fluid
could cause the transmission to overheat. Be sure
to get an accurate reading if you check your
transmission fluid.
Before checking the fluid level, prepare the vehicle as
follows:
1. Start the engine and park the vehicle on a level surface. Keep the engine running.
2. Apply the parking brake and place the shift lever in P (Park).
3. With your foot on the brake pedal, move the shift lever through each gear range, pausing for about
three seconds in each range. Then, move the shift
lever back to P (Park).
4. Allow the engine to idle (500 –800 RPM) for at
least one minute. Slowly release the brake pedal.
5. Keep the engine running and press the Trip/Fuel button or trip odometer reset stem until TRANS
TEMP (Transmission Temperature) displays on the
Driver Information Center (DIC). 6. Using the TRANS TEMP reading, determine and
perform the appropriate check procedure. If the
TRANS TEMP reading is not within the required
temperature ranges, allow the vehicle to cool,
or operate the vehicle until the appropriate
transmission fluid temperature is reached.
Cold Check Procedure
Use this procedure only as a reference to determine if
the transmission has enough fluid to be operated safely
until a hot check procedure can be made. The hot
check procedure is the most accurate method to check
the fluid level. Perform the hot check procedure at the
first opportunity. Use this cold check procedure to check
fluid level when the transmission temperature is
between 24°C and 34°C (75°F and 93°F).
1. Locate the
transmission dipstick at
the rear of the engine
compartment, on the
passenger side of the
vehicle.
See Engine Compartment Overview
on page 6‑4for more information.
2. Pull out the dipstick and wipe it with a clean rag or paper towel.
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3. Install the dipstick by pushing it back in all the way,wait three seconds, and then pull it back out again.
4. Check both sides of the dipstick and read the lower level. Repeat the check procedure to verify the
reading.
5. If the fluid level is below the COLD check band,add only enough fluid as necessary to bring the
level into the COLD band. It does not take much
fluid, generally less than 0.5 Liter (1 Pint). Do not
overfill.
6. Perform a hot check at the first opportunity after the transmission reaches a normal operating
temperature between 60°C and 75°C (140°F
and 167°F).
7. If the fluid level is in the acceptable range, push the dipstick back in all the way.
Hot Check Procedure
Use this procedure to check the transmission fluid level
when the transmission fluid temperature is between
60°C and 75°C (140°F and 167°F).
The hot check is the most accurate method to check
the fluid level. The hot check should be performed at
the first opportunity in order to verify the cold check.
The fluid level rises as fluid temperature increases, so it
is important to ensure the transmission temperature is
within range.
1. Locate thetransmission dipstick at
the rear of the engine
compartment, on the
passenger side of the
vehicle.
See Engine Compartment Overview
on page 6‑4for more information.
2. Pull out the dipstick and wipe it with a clean rag or paper towel.
3. Install the dipstick by pushing it back in all the way, wait three seconds, and then pull it back out again.
4. Check both sides of the dipstick and read the lower level. Repeat the check procedure to verify the
reading.
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5. Safe operating level is within the HOT cross hatchband on the dipstick. If the fluid level is not within
the HOT band, and the transmission temperature
is between 60°C and 75°C (140°F and 167°F),
add or drain fluid as necessary to bring the level
into the HOT band. If the fluid level is low, add only
enough fluid to bring the level into the HOT band.
It does not take much fluid, generally less than
0.5 Liter (1 Pint). Do not overfill.
6. If the fluid level is in the acceptable range, push the dipstick back in all the way.
Consistency of Readings
Always check the fluid level at least twice using the
procedure described previously. Consistency
(repeatable readings) is important to maintaining proper
fluid level. If readings are still inconsistent, contact your
dealer/retailer.
Drive Motor/Generator Control
Module (DMCM) Coolant Surge Tank
Pressure Cap
See Engine Compartment
Overviewon page 6‑4for more information on
location.
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The Drive Motor/Generator Control Module (DMCM)
coolant surge tank pressure cap must be fully installed
on the hybrid coolant surge tank.
Notice:If the pressure cap is not tightly installed,
coolant loss and possible damage to the Drive
Motor/Generator Control Module (DMCM) may occur.
Be sure the cap is properly and tightly secured.
Drive Motor/Generator Control
Module (DMCM) Cooling System
In addition to the regular cooling system, the vehicle
also has a cooling system for the DMCM system.
This system is serviced differently than the vehicle's
main cooling system. The DMCM cooling system
includes the DMCM coolant surge tank, DMCM surge
tank pressure cap, DMCM cooling pumps, hybrid
cooling radiator and the Drive Motor/Generator Control
Module (DMCM). The DMCM cooling system uses a
50/50 pre-mixed DEX-COOL™ coolant and deionized
water available at your dealer/retailer. See “Engine
Coolant” and“Cooling System” in the owner manual for
more information. When you decide it is safe to lift the hood, here is what
you will see:
A. Drive Motor/Generator
Control Module (DMCM)
B. Engine Coolant Surge Tank Pressure Cap
C. DMCM Coolant Surge Tank/Engine Coolant
Surge Tank D. DMCM Cooling
Hoses (Out of View)
E. DMCM Coolant Tank Pressure Cap
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If the coolant inside the DMCM coolant surge tank is
boiling, do not do anything else until it cools down.
The coolant level should be at or above the FULL
COLD mark with the vehicle parked on a level surface.
If it is not, there might be a leak at the DMCM cooler
core, DMCM pressure cap, DMCM cooler hoses,
DMCM cooling pump or somewhere else in the DMCM
cooling system.
Notice:Running the engine when there is a leak in
the hybrid cooling system can cause the hybrid
cooling system to lose all coolant and can damage
the system. Get any leak fixed before you drive the
vehicle or run the engine.
How to Add Coolant to the DMCM
Coolant Surge Tank
If no problem has been found yet, check to see if
coolant is visible in the DMCM coolant surge tank.
If coolant is visible, add pre‐mixed DEX-COOL™
coolant, available at your dealer/retailer, at the DMCM
coolant surge tank, but be sure the DMCM cooling
system, including the DMCM coolant surge tank
pressure cap, is cool before you do it. Use the
procedure following.
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{WARNING:
Steam and scalding liquids from a hot cooling
system can blow out and burn you badly. They are
under pressure, and if you turn the coolant surge
tank pressure cap—even a little —they can come
out at high speed. Never turn the cap when the
cooling system, including the coolant surge tank
pressure cap, is hot. Wait for the cooling system
and coolant surge tank pressure cap to cool if you
ever have to turn the pressure cap.
Notice: Using coolant other than a pre‐mixed
DEX-COOL, available at your dealer/retailer, may
damage your vehicle. Any repairs would not be
covered by your warranty. Always use a pre‐mixed
DEX-COOL (silicate-free) coolant in your vehicle.
{WARNING:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol
and it will burn if the engine parts are hot enough.
Do not spill coolant on a hot engine. If the DMCM coolant is empty , the vehicle must be
serviced by your dealer and a special fill procedure
must be followed.
Notice:
Attempting to fill the DMCM cooling surge
tank yourself when the fluid level is empty can
damage your vehicle. Your vehicle must be
serviced.1. Park the vehicle on a level surface and turn the vehicle off. Remove the DMCM coolant surge tank
pressure cap when the DMCM cooling system,
including the DMCM coolant surge tank pressure
cap and DMCM cooling hoses, are no longer hot.
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