Black plate (21,1)GMC Yukon/Yukon XL Owner Manual - 2011
Instruments and Controls 5-21
Malfunction
Indicator Lamp
A computer system called OBD II
(On-Board Diagnostics-Second
Generation) monitors operation of
the fuel, ignition, and emission
control systems. It ensures that
emissions are at acceptable levels
for the life of the vehicle, helping to
produce a cleaner environment.
This light should come on when the
ignition is on, but the engine is not
running, as a check to show it is
working. If it does not, have the
vehicle serviced by your dealer.If the malfunction indicator lamp
comes on and stays on while the
engine is running, this indicates that
there is an OBD II problem and
service is required.
Malfunctions often are indicated by
the system before any problem is
apparent. Being aware of the light
can prevent more serious damage
to the vehicle. This system assists
the service technician in correctly
diagnosing any malfunction.
Notice:
If the vehicle is
continually driven with this
light on, after a while, the
emission controls might not
work as well, the vehicle fuel
economy might not be as good,
and the engine might not run
as smoothly. This could lead to
costly repairs that might not be
covered by the vehicle warranty. Notice:
Modifications made
to the engine, transmission,
exhaust, intake, or fuel system
of the vehicle or the replacement
of the original tires with other
than those of the same Tire
Performance Criteria (TPC) can
affect the vehicle's emission
controls and can cause this light
to come on. Modifications to
these systems could lead to
costly repairs not covered
by the vehicle warranty. This
could also result in a failure
to pass a required Emission
Inspection/Maintenance test. See
Accessories and Modifications on
page 10‑3.
This light comes on during a
malfunction in one of two ways:
Light Flashing: A misfire
condition has been detected.
A misfire increases vehicle
emissions and could damage the
emission control system on the
vehicle. Diagnosis and service
might be required.
Black plate (44,1)GMC Yukon/Yukon XL Owner Manual - 2011
10-44 Vehicle Care
FusesUsage
36 Windshield Wiper
37 SEO B2 Upfitter Usage
(Battery)
38 Electric Adjustable
Pedals
39 Climate Controls
(Battery)
40 Airbag System (Ignition)
41 Amplifier
42 Audio System
43 Miscellaneous (Ignition),
Cruise Control
44 Liftgate Release
45 Airbag System (Battery)
46 Instrument Panel Cluster
47 Not Used Fuses
Usage
48 Auxiliary Climate Control
(Ignition)
49 Center High-Mounted
Stoplamp (CHMSL)
50 Rear Defogger
51 Heated Mirrors
52 SEO B1 Upfitter Usage
(Battery)
53 Cigarette Lighter,
Auxiliary Power Outlet
54 Automatic Level Control
Compressor Relay
55 Climate Controls
(Ignition)
56 Engine Control Module,
Secondary Fuel Pump
(Ignition) J-Case
Fuses Usage
57 Cooling Fan 1
58 Automatic Level Control
Compressor
59 Heavy Duty Antilock
Braking System
60 Cooling Fan 2
61 Antilock Brake System 1
62 Starter
63 Stud 2 (Trailer Brakes)
64 Left Bussed Electrical
Center 1
65 Electric Running Boards
66 Heated Windshield
Washer System
67 Transfer Case
