Cadillac CT4 2023 Owner's Manual page 94

Malfunctions are often indicated by the
system before any problem is noticeable.
Being aware of the light and seeking service
promptly when it comes on may prevent
damage.
Caution
If the vehicle is driven continually with
this light on, the emission control system
may not work as well, the fuel economy
may be lower, and the vehicle may not
run smoothly. This could lead to costly
repairs that might not be covered by the
vehicle warranty.
Caution
Modifications to the engine, transmission,
exhaust, intake, or fuel system, or the
use of replacement tires that do not
meet the original tire specifications, can
cause this light to come on. This could
lead to costly repairs not covered by the
vehicle warranty. This could also affect
the vehicle s ability to pass an Emissions
Inspection/Maintenance test. See
Accessories and Modifications 0 285.
If the light is flashing : A malfunction has
been detected that could damage the
emission control system and increase vehicle
emissions. Diagnosis and service may be
required.
To help prevent damage, reduce vehicle
speed and avoid hard accelerations and
uphill grades. If towing a trailer, reduce the
amount of cargo being hauled as soon as
possible.
If the light continues to flash, find a safe
place to park. Turn the vehicle off and wait
at least 10 seconds before restarting the
engine. If the light is still flashing, follow
the previous guidelines and see your dealer
for service as soon as possible.
If the light is on steady : A malfunction has
been detected. Diagnosis and service may be
required.
Check the following:
If fuel has been added to the vehicle
using the capless fuel funnel adapter,
make sure that it has been removed. See
Filling the Tank with a Portable Gas Can
under Filling the Tank 0 275. The
diagnostic system can detect if the
adapter has been left installed in the
vehicle, allowing fuel to evaporate into
Instruments and Controls
the atmosphere. A few driving trips with
the adapter removed may turn off the
light.
Poor fuel quality can cause inefficient
engine operation and poor driveability,
which may go away once the engine is
warmed up. If this occurs, change the fuel
brand. It may require at least one full
tank of the proper fuel to turn the light
off. See Recommended Fuel (LSY 2.0L L4
Turbo Engine) 0 274 or
Recommended Fuel (L3B 2.7L L4 Turbo and
LF4 3.6L V6 Twin Turbo Engines) 0 275.
If the light remains on, see your dealer.
Emissions Inspection and Maintenance
Programs
If the vehicle requires an Emissions
Inspection/Maintenance test, the test
equipment will likely connect to the
vehicle's Data Link Connector (DLC).
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