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9. If the trailer wheels lockup (indicated by squealingtires), reduce the GAIN setting; if the trailer wheels
turn freely, increase the GAIN setting.
Repeat Steps 8 and 9 until the GAIN setting is at a point
just below trailer wheel lockup. If towing a heavier trailer, trailer wheel lockup may not be attainable even
with the maximum GAIN setting of 10.
Light Electric Heavy Electric Light EOH
Heavy EOH
Type of Trailer
Brakes Electric Trailer
BrakesElectric Trailer
BrakesElectric over Hy-
draulic Trailer
BrakesElectric over Hy-
draulic Trailer
Brakes
Load *Under 10,000 lbs *Above 10,000 lbs *Under 10,000 lbs *Above 10,000 lbs
* The suggested selection depends and may change
depending on the customer preferences for braking per-
formance. Condition of the trailer brakes, driving and
road state may also affect the selection.
EVIC Display Messages
The trailer brake control interacts with the Electronic
Vehicle Information Center (EVIC). Display messages, along with a single chime, will be displayed when a
malfunction is determined in the trailer connection,
trailer brake control, or on the trailer. Refer to “Electronic
Vehicle Information Center” in “Understanding Your
Instrument Panel” for further information.
552 STARTING AND OPERATING
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ONBOARD DIAGNOSTIC SYSTEM (OBD II)
Your vehicle is equipped with a sophisticated onboard
diagnostic system called OBD II. This system monitors
the performance of the emissions, engine, and automatic
transmission control systems. When these systems are
operating properly, your vehicle will provide excellent
performance and fuel economy, as well as engine emis-
sions well within current government regulations.
If any of these systems require service, the OBD II system
will turn on the “Malfunction Indicator Light (MIL).” It
will also store diagnostic codes and other information to
assist your service technician in making repairs. Al-
though your vehicle will usually be drivable and not
need towing, see your authorized dealer for service as
soon as possible.
CAUTION!
•Prolonged driving with the MIL on could cause
further damage to the emission control system. It
could also affect fuel economy and drivability. The
vehicle must be serviced before any emissions tests
can be performed.
• If the MIL is flashing, while the engine is running,
severe catalytic converter damage and power loss
will soon occur. Immediate service is required.
Loose Fuel Filler Cap Message
If the vehicle diagnostic system determines
that the fuel filler cap is loose, improperly
installed, or damaged, a loose gascap indicator
will display in the EVIC telltale display area.
Refer to “Electronic Vehicle Information Center (EVIC) in7
MAINTAINING YOUR VEHICLE 633
Page 661 of 734

CAUTION!
•Using a transmission fluid other than the manufac-
turer’s recommended fluid may cause deterioration
in transmission shift quality and/or torque con-
verter shudder, and will require more frequent
fluid and filter changes. Refer to “Fluids, Lubri-
cants, and Genuine Parts” in “Maintaining Your
Vehicle” for fluid specifications.
Special Additives
The manufacturer strongly recommends against using
any special additives in the transmission. Automatic
Transmission Fluid (ATF) is an engineered product and
its performance may be impaired by supplemental addi-
tives. Therefore, do not add any fluid additives to the
transmission. The only exception to this policy is the use of special dyes for diagnosing fluid leaks. Avoid using
transmission sealers as they may adversely affect seals.
CAUTION!
Do not use chemical flushes in your transmission as
the chemicals can damage your transmission compo-
nents. Such damage is not covered by the New
Vehicle Limited Warranty.
Fluid Level Check - Six-Speed Transmission
It is best to check the fluid level when the transmission is
at normal operating temperature (170-180°F / 77-82°C).
This normally occurs after at least 15 miles (25 km) of
driving. At normal operating temperature the fluid can-
not be held comfortably between the fingertips. You can
read the transmission sump temperature in the EVIC
display (see Electronic Vehicle Information Center [EVIC]
for further information).
7
MAINTAINING YOUR VEHICLE 659
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Use the following procedure to check the transmission
fluid level properly:
1. Monitor the transmission temperature using the EVICdisplay, and operate the vehicle as required to reach
the normal operating temperature.
2. Park the vehicle on level ground.
3. Run the engine at normal idle speed for at least 60 seconds, and leave the engine running for the rest of
this procedure.
4. Fully apply the parking brake and press the brake pedal.
5. Place the shift lever momentarily into each gear posi- tion (allowing time for the transmission to fully en-
gage in each position), ending with the lever in PARK.
6. Remove the dipstick, wipe it clean and reinsert it until seated. 7. Remove the dipstick again and note the fluid level on
both sides. The fluid level reading is only valid if there
is a solid coating of oil on both sides of the dipstick.
Note that the holes in the dipstick will be full of fluid
if the actual level is at or above the hole. The fluid level
should be between the “HOT” (upper) reference holes
on the dipstick at normal operating temperature. If the
fluid level is low, add fluid through the dipstick tube
to bring it to the proper level. Do not overfill.Use
ONLY the recommended fluid (see Fluids, Lubri-
cants, and Genuine Parts for fluid specifications).
After adding any quantity of oil through the dipstick
tube, wait a minimum of two minutes for the oil to
fully drain into the transmission before rechecking the
fluid level.
660 MAINTAINING YOUR VEHICLE
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MAINTENANCE SCHEDULE
Your vehicle is equipped with an automatic oil change
indicator system. The oil change indicator system will
remind you that it is time to take your vehicle in for
scheduled maintenance.
Based on engine operation conditions, the oil change
indicator message will illuminate. This means that ser-
vice is required for your vehicle. Operating conditions
such as frequent short-trips, trailer tow, extremely hot or
cold ambient temperatures, and E85 fuel usage will
influence when the “Oil Change Required” message is
displayed. Severe Operating Conditions can cause the
change oil message to illuminate as early as 3,500 miles
(5,600 km) since last reset. Have your vehicle serviced as
soon as possible, within the next 500 miles (805 km).
Your authorized dealer will reset the oil change indicator
message after completing the scheduled oil change. If a
scheduled oil change is performed by someone other thanyour authorized dealer, the message can be reset by refer-
ring to the steps described under “Electronic Vehicle Infor-
mation Center (EVIC)/Oil Change Required” in “Under-
standing Your Instrument Panel” for further information.
NOTE:
Under no circumstances should oil change inter-
vals exceed 10,000 miles (16,000 km) or twelve months,
whichever comes first.
Once A Month Or Before A Long Trip:
• Check engine oil level
• Check windshield washer fluid level
• Check the tire inflation pressures and look for unusual
wear or damage
• Check the fluid levels of the coolant reservoir, brake
master cylinder, power steering (2500/3500 Models
Only) and transmission as needed
• Check function of all interior and exterior lights
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S696 MAINTENANCE SCHEDULES