Malfunction Indicator Lamp
Service Engine Soon Light in the
United States or Check Engine Light
in Canada
Your vehicle is equipped with a computer which
monitors operation of the fuel, ignition, and emission
control systems.
This system is called OBD II (On-Board
Diagnostics-Second Generation) and is intended to
assure that emissions are at acceptable levels for the life
of the vehicle, helping to produce a cleaner environment.
The SERVICE ENGINE SOON or CHECK ENGINE light
comes on to indicate that there is a problem and service
is required. Malfunctions often will be indicated by the
system before any problem is apparent. This may prevent
more serious damage to your vehicle. This system is also
designed to assist your service technician in correctly
diagnosing any malfunction.
Notice: If you keep driving your vehicle with this
light on, after a while, your emission controls may
not work as well, your fuel economy may not be as
good, and your engine may not run as smoothly.
This could lead to costly repairs that may not be
covered by your warranty.
Notice: Modifications made to the engine,
transmission, exhaust, intake, or fuel system of
your vehicle or the replacement of the original tires
with other than those of the same Tire Performance
Criteria (TPC) can affect your vehicle’s emission
controls and may cause this light to come on.
Modifications to these systems could lead to costly
repairs not covered by your warranty. This may
also result in a failure to pass a required Emission
Inspection/Maintenance test.
United States
Canada
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Summary of Contents for 2004 Envoy
Page 5: ...These are some examples of symbols that may be found on the vehicle v ...
Page 6: ... NOTES vi ...
Page 123: ... NOTES 3 3 ...
Page 124: ...Instrument Panel Overview 3 4 ...
Page 322: ...When you open the hood on the V8 engine you ll see the following 5 14 ...
Page 406: ...L6 Engine 5 98 ...
Page 409: ...V8 Engine 5 101 ...
Page 412: ...Rear Underseat Fuse Block Envoy Envoy 5 104 ...
Page 450: ... NOTES 7 14 ...