Cadillac 2010 DTS - Manual (Page 223)

Light On Steady: An emission control system
malfunction has been detected on the vehicle.
Diagnosis and service might be required.
An emission system malfunction might be corrected by
doing the following:
. Make sure the fuel cap is fully installed. See Filling
the Tank on page 6‑8. The diagnostic system
can determine if the fuel cap has been left off or
improperly installed. A loose or missing fuel cap
allows fuel to evaporate into the atmosphere. A few
driving trips with the cap properly installed should
turn the light off.
. If the vehicle has been driven through a deep
puddle of water, the vehicle's electrical system
might be wet. The condition is usually corrected
when the electrical system dries out. A few driving
trips should turn the light off.
. Make sure to fuel the vehicle with quality fuel.
Poor fuel quality causes the engine not to run as
efficiently as designed and can cause: stalling
after start-up, stalling when the vehicle is changed
into gear, misfiring, hesitation on acceleration,
or stumbling on acceleration. These conditions
might go away once the engine is warmed up.
If one or more of these conditions occurs, change
the fuel brand used. It will require at least one
full tank of the proper fuel to turn the light off.
See Gasoline Octane on page 6‑5.
If none of the above have made the light turn off,
your dealer can check the vehicle. The dealer has the
proper test equipment and diagnostic tools to fix any
mechanical or electrical problems that might have
developed.
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