Mercury 1996 Sable Manual page 108

Service engine soon light
This light comes on when you turn the ignition
key to ON, but should turn off when the engine
starts. If the light does not come on when you
turn the ignition to ON or if it comes on and
stays on when you are driving, have your
vehicle serviced as soon as possible. This
indicates a possible problem with one of the
vehicle's emission control systems. You do not
need to have your vehicle towed in.
If the light turns on and off at one (1) second
intervals while you are driving the vehicle, it
means that the engine is misfiring. If this
condition persists, damage could occur to the
engine or catalytic converter. Avoid heavy
acceleration and have your vehicle serviced at
the first opportunity. You do not need to have
your vehicle towed in.
If the light turns on and off on rare occasions
while you are driving, it means that a
malfunction occurred and the condition corrected
itself.
An example of a condition which corrects itself
occurs when an engine running out of fuel
begins to misfire. In this case, the Service Engine
Soon Warning Light may turn on and will then
set a Diagnostic Trouble Code indicating that the
engine was misfiring while the last of the fuel
was being consumed. After refueling, the Service
Engine Soon Warning Light will turn off after
the vehicle has completed three consecutive
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