Mercedes-Benz 300 E 1990 Owner's Manual page 74

Emission Control
Certain systems of the engine
serve to keep the toxic compo­
nents of the exhaust gases within
permissible limits required by law.
These systems, of course, will
function properly only when
maintained strictly according to
factory specifications. Any ad­
justments on the engine should,
therefore, be carried out only by
qualified MERCEDES-BENZ
technicians. The engine should
not be altered in any way. More­
over, the specified service and
maintenance jobs must be carried
out regularly according to
MERCEDES-BENZ servicing
requirements. For details refer to
the Maintenance Booklet.
72
Warning!
Inhalation of exhaust gas is
hazardous to your health. All
exhaust gas contains carbon
monoxide, and inhaling it can
cause unconsciousness and
lead to death.
Do not run the engine in con­
fined areas (such as a garage)
which are not properly ven­
tilated. If you think that ex­
haust gas fumes are entering
the vehicle while driving, have
the cause determined and
corrected immediately. If you
must drive under these con­
ditions, drive only with at least
one window fully open.
On-Board Diagnostic System
(California models only)
The CIS-E control unit monitors
emission control components that
either provide input signals to or
receive output signals from the
control unit. Malfunctions resulting
from interruptions or failure of any
of these components are indicated
by the "CHECK ENGINE" indi­
cator lamp in the instrument
cluster and are simultaneously
stored in the CIS-E control unit.
If the "CHECK ENGINE" indicator
lamp comes on, have the system
checked at your authorized
MERCEDES-BENZ dealer at the
first opportunity.
An on-board test connection with
pushbutton and light emitting
diode (LED) is located on the en­
gine compartment firewall, allow­
ing the accurate detection of
system malfunctions.