1999 GMC C-SERIES check engine

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7-21
(25) = Check thermostatically controlled air cleaner
installation to make certain that all ducts are connected and
correctly installed. Also, check valve for proper operation.
(26) = Evaporative Control System Service (if equipped):
Check all fuel and vapor lines and hoses for proper
connections and correct routing (or every 24 months,
whichever occurs first). Replace parts as needed.
(27) = Replace air cleaner filter (or every 24 months,
whichever occurs first). Replace filter more often if
driving in dusty conditions. Ask your dealer for the
proper replacement intervals for your driving conditions.
(28) = Replace spark plugs. Inspect wires for damage.
Check the wire boot and boot heat shield fit at spark
plugs and coil. Replace parts as needed.
(30) = Check the fuel tank, fuel cap and fuel lines for
damage which could cause leakage. Inspect fuel cap for
correct sealing ability and any indications of damage.
Check fuel cap gasket for even filler neck imprint.
Replace parts as needed.
(31) = Check EGR system as described in the service
manual. See ªService and Owner Publicationsº in the Index.
(32) = Inspect Electronic Vacuum Regulator Valve
(EVRV) filter for excessive contamination or plugging.
If needed, clean filter with solution of soap and water,
let dry and install.(33) = Check the PCV system for proper operation and
clean PCV valve. Replace hoses as needed.
(34) = Replace PCV valve and blow out the PCV valve
hose with compressed air. Replace hoses as needed.
(35) = Drain, flush and refill cooling system. See
ªRecommended Fluids and Lubricantsº in the Index for
what to use. Inspect hoses. Clean radiator, condenser,
pressure cap and neck. Pressure test cooling system and
pressure cap. For Caterpillar
 diesel engines, always refer
to the Caterpillar Diesel Engine Operation & Maintenance
Manual for coolant recommendations and change intervals.
(37) = Rear axle service: Change the lubricant. See
ªRecommended Fluids and Lubricantsº in the Index.
(38) = Front axle service: Re
-pack upper kingpin
roller bearing.
(39) = Air brake service:

Inspect brake lines and hoses for proper hook
-up,
binding, leaks, cracks, chafing, etc. Inspect drum
brake linings for wear or cracks. Inspect other brake
parts at each wheel, including drums, wheel cylinders
and piston heat shields and boots. Check brake pedal
for excessive free play or travel (or every 6 months,
whichever occurs first) and have serviced if needed.
Check brakes more often if driving habits and
conditions result in frequent braking.
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7-23
Part B: Owner Checks and Services
Listed in this part are owner checks and services which
should be performed at the intervals specified to help
ensure the safety, dependability and emission control
performance of your vehicle.
For your safety and that of others, any of the
safety
-related components that may have been damaged
in an accident should be checked and any needed repairs
made before operating the vehicle.
At the minimum, these routine checks should be made
every 6 months or 6,000 miles (10 000 km), whichever
occurs first. Whenever repairs are needed, have them
completed before operating the vehicle.
At Each Fuel Fill
It is important for you or a service station attendant to
perform these underhood checks at each fuel fill.Engine Oil Level Check
Check the engine oil level and add the proper oil if
necessary. See ªEngine Oilº in the Index for
further details.
Engine Coolant Level Check
Check the engine coolant level and add DEX
-COOL

coolant mixture if necessary. See ªEngine Coolantº in
the Index for further details.
Windshield Washer Fluid Level Check
Check the windshield washer fluid level in the
windshield washer tank and add the proper fluid if
necessary. See ªWindshield Washer Fluidº in the Index
for further details.
Tire Inflation Check
Check tire inflation cold. Make sure tires are inflated to
the pressures specified on the Certification/Tire label.
See ªTiresº in the Index for further details.
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7-25
Starter Switch Check
CAUTION:
When you are doing this check, the vehicle could
move suddenly. If it does, you or others could be
injured. Follow the steps below.
1. Before you start, be sure you have enough room
around the vehicle.
2. Firmly apply both the parking brake (see ªParking
Brakeº in the Index if necessary) and the
regular brakes.
NOTE: Do not use the accelerator pedal, and be
ready to turn off the engine immediately if it starts.
3. On automatic transmission vehicles, try to start the
engine in each gear. The starter should work only in
PARK (P), if equipped, or NEUTRAL (N). If the
starter works in any other position, your vehicle
needs service.Automatic Transmission Shift Indicator Check
Check that the indicator points to the gear chosen.
Steering Check
Be alert for any changes in steering action, abnormal
front tire wear or steering wheel position. An inspection
or service is needed when the steering wheel is harder to
turn or has too much free play, or if there are strange
sounds when turning or parking.
Brake System Check
Be alert to illumination of the low air warning lamp or
for the tone alarm, or changes in braking action, such as
repeated pulling to one side, unusual sounds when
braking or increased brake pedal travel. Make sure air
brake system reservoirs are drained daily with full
system air pressure, and check system for leaks. Any of
these conditions could indicate the need for brake
system inspection and/or service.
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7-26
Engine Cooling System Service
Inspect the hoses and have them replaced if they are
cracked, swollen or deteriorated. Inspect all pipes,
fittings and clamps; replace as needed. Clean the outside
of the radiator and air conditioning condenser. To help
ensure proper operation, a pressure test of the cooling
system and pressure cap is recommended at least once
a year.
Exhaust System Check
Be alert for any changes in the sound of the exhaust
system or any smell of fumes. These are signs the
system may be leaking. Have it checked and/or repaired
at once. Refer to ªEngine Exhaustº and ªRunning Your
Engine While You're Parkedº in the Index.
Windshield Wipers and Washers Check
Check operation and condition of the wiper blades.
Check the flow of the washer spray.
Defroster Check
Move the control to the defrost symbol and the fan to HI
or the high symbol. Then check the airflow from the
ducts at the inside base of the windshield.Mirrors and Sun Visors Check
Check that friction joints hold mirrors and sun visors
in place.
Seat Adjuster Check
When adjusting a manual seat, be sure seat adjusters
latch by attempting to move the seat after latching.
Lamps Check
Check panel lighting, warning lights, indicator lights
and interior lamps. On the outside, check: license plate
lamps, sidemarker lamps, reflectors or lights on outside
mirrors, headlamps, parking lamps, identification and
clearance lamps, taillamps, brake lamps, turn signals,
backup lamps and hazard warning flashers. Have
headlamp aim checked at once if beams seem
improperly aimed.
Glass, Mirrors, Lamps and/or Reflectors
Condition Check
Look for broken, scratched, dirty or damaged glass,
mirrors, lamps or reflectors that could reduce the view
or visibility or cause injury. Replace, clean or
repair promptly.
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7-27
Door Latches Check
Check that doors close, latch and lock tightly. Check for
broken, damaged or missing parts that might prevent
tight latching.
Hood Latches Check
Check that the hood closes firmly. Check for broken,
damaged, loose or missing parts that might prevent tight
latching. Make sure the secondary latch (if equipped)
keeps the hood from opening all the way when the
primary latch is released.
Fluid Leaks Check
Check for fuel, coolant, oil or other fluid leaks by
looking at the surface beneath the vehicle after it has
been parked for a while.
Underbody Inspection
Corrosive materials used for ice, snow removal and dust
control can collect on the underbody. If these materials
are not removed, accelerated corrosion (rust) can occur
on underbody parts such as fuel lines, frame, floor pan
and exhaust system. At least every spring, flush these materials from the underbody with plain water. Take
care to clean well any areas where mud and other debris
can collect. Sediment packed in closed areas of the
frame should be loosened before being flushed.
Engine Cover Check
Check that the cab's engine cover and seal (if equipped)
are not torn or damaged. Be sure that the cover is bolted
down firmly to the floor.
At Least Once a Year
Key Lock Cylinders Service
Lubricate the key lock cylinders with the lubricant
specified in Part C.
Underbody Flushing Service
At least every spring, use plain water to flush any
corrosive materials from the underbody. Take care to
clean thoroughly any areas where mud and other debris
can collect.
Tractor Protection (Breakaway) Valve Check
On air brake models, remove, disassemble, clean and
inspect the tractor protection (breakaway) valve.
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8-8
CURRENT PUBLICATIONS FOR 1999 GMC
SERVICE MANUALS
Service Manuals have the diagnosis and repair information
on engines, transmission, axle, suspension, brakes,
electrical, steering, body, etc.
RETAIL SELL PRICE: $90.00
TRANSMISSION, TRANSAXLE, TRANSFER CASE
UNIT REPAIR MANUAL
This manual provides information on unit repair service
procedures, adjustments and specifications for the
1999 GM transmissions, transaxles and transfer cases.
RETAIL SELL PRICE: $50.00
SERVICE BULLETINS
Service Bulletins give technical service information needed
to knowledgeably service General Motors cars and trucks.
Each bulletin contains instructions to assist in the
diagnosis and service of your vehicle.OWNER'S INFORMATION
Owner publications are written directly for Owners and
intended to provide basic operational information about the
vehicle. The owner's manual will include the Maintenance
Schedule for all models.
In-Portfolio: Includes a Portfolio, Owner's Manual and
Warranty Booklet.
RETAIL SELL PRICE: $15.00
Without Portfolio: Owner's Manual only.
RETAIL SELL PRICE: $10.00
CURRENT & PAST MODEL ORDER FORMS
Service Publications are available for current and past
model GM vehicles. To request an order form, please
specify year and model name of the vehicle.
PLEASE COMPLETE THE ORDER FORM SHOWN ON
THE FOLLOWING PAGE AND MAIL TO:
Helm, Incorporated
P.O. Box 07130
Detroit, MI 48207OR ORDER TOLL FREE: 1-800-551-4123
Monday-Friday 8:00 AM ± 6:00 PM Eastern Time
For Credit Card Orders Only (VISA±MasterCard±Discover)
1999 GMC SERVICE PUBLICATIONS ORDERING INFORMATION
The following publications covering the operation and servicing of your vehicle can be purchased by filling out
the Service Publication Order Form in this book and mailing it in with your check, money order,
or credit card information to Helm, Incorporated (address below.)
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9-2
Brake (Continued)
Four-Wheel and Six-Wheel Drum 6-33 . . . . . . . . . . . . . . .
Four-Wheel Disc 6-32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hydraulic Systems 4-7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Master Cylinder 6-30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parking 2-23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pedal Travel 6-33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Propshaft Brake Burnish Procedure 2-24 . . . . . . . . . . . . . . .
Releasing Air-Operated Parking Brakes 5-15 . . . . . . . . . . .
Replacing System Parts 6-35 . . . . . . . . . . . . . . . . . . . . . . . .
System Check 7-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Warning Lights 2-57 . . . . . . . . . . . . . . . . . . . . . . . .
Brake, Anti-Lock 4-7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Braking 4-6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Braking in Emergencies 4-9 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Break-In, New Vehicle 2-5 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Capacities and Specifications 6-74 . . . . . . . . . . . . . . . . . . . .
Carbon Monoxide 2-29, 2-30 , 4-27 . . . . . . . . . . . . . . . . . . .
Cassette Tape Player Care 3-12 . . . . . . . . . . . . . . . . . . . . . . . .
Center Passenger Position 1-22 . . . . . . . . . . . . . . . . . . . . . . . .
Certification/Tire Label 4-28, 6-67 . . . . . . . . . . . . . . . . . . . . .
Changing a Flat Tire 5-34 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Charging System Light 2-56 . . . . . . . . . . . . . . . . . . . . . . . . . .
Chassis Lubrication 6-37 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Check Gages Light 2-67 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking Your Restraint Systems 1-36 . . . . . . . . . . . . . . . . . .
Chemical Paint Spotting 6-65 . . . . . . . . . . . . . . . . . . . . . . . . . . Child Restraints 1
-26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Securing in the Center Seat Position 1-31 . . . . . . . . . . . . . .
Top Strap 1-30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cigarette Lighter 2-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Breaker Block, Instrument Panel 6-69 . . . . . . . . . . . . .
Cleaner, Air 6-17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cleaning
Fabric 6
-59 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Glass 6-62 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inside of Your Vehicle 6-59 . . . . . . . . . . . . . . . . . . . . . . . . .
Instrument Panel 6-61 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Outside of Your Vehicle 6-63 . . . . . . . . . . . . . . . . . . . . . . . .
Safety Belts 6-61 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Special Problems 6-60 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tires 6-64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Vinyl 6-61 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Windshield and Wiper Blades 6-62 . . . . . . . . . . . . . . . . . . .
Clock, Setting the 3-7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clutch Pedal Free Travel 6-37 . . . . . . . . . . . . . . . . . . . . . . . . .
Comfort Controls 3-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Component Box 6-44 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Connections, Trailer 2-49 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Control of a Vehicle 4-6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant 6-23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heater, Engine 2-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Recovery Tank 5-22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surge Tank 5-29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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9-3
Cooling System
Capacity 6-74 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diesel Engines 5-27, 6-25 . . . . . . . . . . . . . . . . . . . . . . . . . .
Gasoline Engines 5-20, 6-23 . . . . . . . . . . . . . . . . . . . . . . . .
Crankcase Capacity 6-74 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cruise Control 2-36 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Customer Assistance for Text Telephone Users 8-3 . . . . . . . . .
Customer Assistance Information 8-1 . . . . . . . . . . . . . . . . . . .
Customer Satisfaction Procedure 8-2 . . . . . . . . . . . . . . . . . . . .
Damage
Finish 6-65 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sheet Metal 6-64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Daytime Running Lamps 2-44 . . . . . . . . . . . . . . . . . . . . . . . . .
Daytime Running Lamps Indicator Light 2-67 . . . . . . . . . . . .
Defects, Reporting Safety 8-6, 8-7 . . . . . . . . . . . . . . . . . . . . .
Defensive Driving 4-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Defogging 3-6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diesel Engine Exhaust Brake 2-16 . . . . . . . . . . . . . . . . . . . . . .
Diff Lock Indicator Light 2-63 . . . . . . . . . . . . . . . . . . . . . . . . .
Do Not Shift Light 2-57 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dome Lamps 2-46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Door
Latches Check 7
-27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Locks 2-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Locks 2-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driver Position 1-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driving
City 4
-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Defensive 4-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Drunken 4
-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Freeway 4-20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
In a Blizzard 4-26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
In Rain and on Wet Roads 4-16 . . . . . . . . . . . . . . . . . . . . . .
Night 4-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
On Curves 4-10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
On Hill and Mountain Roads 4-22 . . . . . . . . . . . . . . . . . . . .
On Snow and Ice 4-24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Through Water 4-18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Winter 4-24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Drunken Driving 4-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical Equipment, Adding 6-68 . . . . . . . . . . . . . . . . . . . .
Electrical System 6-68 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine
Air Cleaner Filter 6
-77 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air Control 2-42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Automatic Shutdown 2-11 . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant (Caterpillar
Diesel Engine) 6-27 . . . . . . . . . . . . .
Coolant (Gasoline Engine) 6-23 . . . . . . . . . . . . . . . . . . . . . .
Coolant Heater 2-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Level Check 7-23 . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Temperature Gage 2-62 . . . . . . . . . . . . . . . . . . . . .
Cooling System Capacity 6-74 . . . . . . . . . . . . . . . . . . . . . . .
Crankcase Capacity 6-74 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diesel,Warm-Up 2-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exhaust 2-29, 2-30, 4-27 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fan Breakage 6-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fan Noise 5-33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fast Idle System 2-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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