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Engine Oil Life System (Gasoline
Engine)
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 light will come on. See
Change Engine Oil Light on page 3-38. 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 service people 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 light
being turned on, reset the system.
To reset the change engine oil light:
1. Turn the ignition key to ON/RUN with the
engine off.
2. Fully press and release the accelerator pedal slowly
three times within 10 seconds.
If the change engine oil light flashes for
five seconds, the system is resetting.
3. Turn the key to OFF.
If the change engine oil light comes back on when you
start your vehicle, the engine oil life system has not
reset. Repeat the procedure.
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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 light
being turned on, reset the system.
To reset the Engine Oil Life System:
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.
If the change engine oil light is turned off, the
system is resetting.
3. Turn the key to OFF.
If the change engine oil light comes back on when you
start your vehicle, the Engine Oil Life System has not
reset. Repeat the procedure.
What to Do with Used Oil
Used engine oil contains certain elements that can be
unhealthy for your skin and could even cause cancer.
Do not let used oil stay on your skin for very long. Clean
your skin and nails with soap and water, or a good hand
cleaner. Wash or properly dispose of clothing or rags
containing used engine oil. See the manufacturer’s
warnings about the use and disposal of oil products.
Used oil can be a threat to the environment. If you
change your own oil, be sure to drain all the oil from the
filter before disposal. Never dispose of oil by putting it
in the trash, pouring it on the ground, into sewers, or into
streams or bodies of water. Instead, recycle it by taking
it to a place that collects used oil. If you have a problem
properly disposing of used oil, ask your dealer/retailer, a
service station, or a local recycling center for help.
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Page 243 of 384
Engine Oil Life System
(Caterpillar
®Diesel Engine)
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 light
being turned on, reset the system.
To reset the Engine Oil Life System:
1. Turn the ignition key to ON/RUN with the
engine off.
2. Fully apply and hold the brake pedal while you fully
press and release the accelerator pedal, pausing
slightly at each press and each release, three times
within five seconds.
3. Turn the key to OFF.
If the change engine oil light comes back on when you
start your vehicle, the Engine Oil Life System has
not reset. Repeat the procedure.
Engine Air Cleaner/Filter
DURAMAX®Diesel
6.6L EngineV8 Gas and CAT and
Isuzu 6H Diesel Engines
5-39
Page 261 of 384
Brakes
Brake Fluid
If your vehicle has
hydraulic brakes, there is a
brake master cylinder in
the engine compartment
on the driver side of the
vehicle.
Refer to the Maintenance Schedule to determine when
to check the brake fluid.
{CAUTION:
Do not add brake uid before you check the
level. If you do, you could get too much brake
uid. Brake uid could spill on the hot engine
and it can catch re. You could be burned and
your vehicle could be damaged. See “Checking
Brake Fluid” in this section.
Checking Brake Fluid
Apply the brake pedal several times with the ignition off.
The brake fluid reservoir is in the engine compartment
on the driver side of the vehicle. Clean one of the
reservoir caps and the area around the cap, and
remove it.
The fluid level should be
even with the bottom ring
of the filler opening. If it is
low, add enough fluid to fill
the reservoir to the proper
level.
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Page 272 of 384

Notice:If you leave your radio or other accessories
on during the jump starting procedure, they could
be damaged. The repairs would not be covered
by your warranty. Always turn off your radio and
other accessories when jump starting your vehicle.
3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or accessory power outlets. Turn off the
radio and all lamps that are not needed. This will
avoid sparks and help save both batteries, and
it could save the radio!
4. Open the hood on the other vehicle and locate the
positive (+) and the negative (−) terminal locations
on that vehicle.
Open the hood on your
vehicle and find the remote
positive (+) terminal,
located under a red plastic
cover on the passenger’s
side of the vehicle.
Squeeze the tab to open
the cover and access the
remote positive (+)
terminal.You will not see the battery (or batteries) of your
vehicle under the hood. They are located in a frame
mounted battery box, which is located on either
the driver’s or the passenger’s side of the vehicle.
You will not need to access your battery
(or batteries) for jump starting. The remote
positive (+) terminal is for that purpose.
{CAUTION:
Using a match near a battery can cause battery
gas to explode. People have been hurt doing
this, and some have been blinded. Use a
ashlight if you need more light.
Be sure the batteries have enough water. You
do not need to add water to the ACDelco
®
battery (or batteries) installed in your new
vehicle. But if a battery has ller caps, be sure
the right amount of uid is there. If it is low,
add water to take care of that rst. If you do
not, explosive gas could be present.
Battery uid contains acid that can burn you.
Do not get it on you. If you accidentally get it
in your eyes or on your skin, ush the place
with water and get medical help immediately.
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Page 309 of 384
Fuse Usage
13Trailer Turn Signals/Hazard Warning
Flashers
14 Radio/Chime
15 Daytime Running Lamps
16 Airbag System
17 Exterior/Interior Lamps
18 Parking Brake
19 Accessory Power
20 Ignition 4
21 Sidemarker Lamps
22 Turn Signal/Backup Lamps
23 Transmission
24 Hydraulics/Air Brake
A Spare
B SpareFuse Usage
Blank Not Used
BRK Brake Warning Lamp
RT PRK Passenger Side Parking Lamps
Blank Not Used
Blank Not Used
LT PARK Driver Side Parking Lamps
RT REAR
TRN/STOPPassenger Side Rear Turn
Signal/Stoplamp
LT REAR
TRN/STOPDriver Side Rear Turn
Signal/Stoplamp
RADIO Radio
Blank Not Used
Blank Not Used
PWR WNDW Power Windows
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Page 310 of 384

Relay Usage
ECU/PTO*Engine Control Unit/Power Take-Off
*Diesel 7.8 DURAMAX
®
BRK LAMPC4/C5 Brake Lamps,
C6/C7/C8 Tractor/Trailer Wiring
DRL Daytime Running Lamps
IGN-4 Ignition
CHMSL Center High Mounted Stoplamp
MRK LTS Sidemarker and Clearance Lamps
HTD/MIRR Heated Mirrors
HTR Diesel Heated Fuel
RT TRN TRLR Passenger Side Trailer Turn Signal
Blank Not Used
LT TRN TRLR Driver Side Trailer Turn Signal
Blank Not Used
Blank Not Used
Blank Not Used
Underhood Fuse Block
When a circuit goes out, the problem could be in either
the primary or secondary underhood fuse blocks.
These blocks use blade-type fuses.
Both underhood fuse blocks are located in the engine
compartment, on the passenger side of the vehicle.To access the fuse blocks, gently squeeze both sides of
the cover to unlatch the tabs at the top. Then, unsnap
both attachments at the bottom and remove the cover.
Notice:Spilling liquid on any electrical components
on your vehicle may damage it. Always keep the
covers on any electrical component.
Be sure to replace fuses with fuses of the same rating.
Do not use fuses of higher amperage than those
indicated on the fuse block.
Primary Underhood Fuse Block
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Fuse Usage
RR DEFOG Rear Defogger
ENG 1 Engine 1
ENG 3 Engine 3 (L18/LF6/LF8)
PCM-B Powertrain Control Module
TCM Transmissions (LF8)
ENG 4 Engine 4 (LMM/LF6/LF8)
ENG 2 Engine 2 (L18/LMM)
HTD FUEL Heated Fuel (LMM)
BLANK Not Used
BLANK Not Used
NOTE 3 Fan Relay (LMM), Emissions (L18)
A/C COMP Air Conditioning Compressor
ABS 1 Antilock Brake System 1
ABS 2 Antilock Brake System 2
ABS 3 Antilock Brake System 3
ENGINE Engine
E/A PUMP Electronic/Automatic Pump
HORN HornFuse Usage
NOTE 2Fuel (L18/LMM), Electronic Control
Module (LF6)
NOTE 4 Electronic Control Module (LF6)
STUD A Spare
STUD B Spare
Relay Usage
NOTE 1 LMM/L18 Fuel Pump Relay
IGN B RELAY Ignition Relay
STARTER
RELAYStarter Relay
HORN RELAY Horn Relay
IGN A RELAY Ignition Relay
PTO/ECU*
RELAYPower Take-Off/Engine Control Unit
(*Diesel 7.8L LF8)
REVERSE
RELAYReverse Relay
FAN RELAY Fan Relay (LMM)
5-107