Dodge 2009 Ram 1500 - Manual (Page 430)

ONBOARD DIAGNOSTIC SYSTEM (OBD II)
Your vehicle is equipped with a sophisticated onboard
diagnostic system called OBDII. This system monitors
the performance of the emissions, engine, and automatic
transmission control systems. When these systems are
operating properly, your vehicle will provide excellent
performance and fuel economy, as well as engine emis-
sions well within current government regulations.
If any of these systems require service, the OBD II system
will turn on the Malfunction Indicator Light (MIL). It will
also store diagnostic codes and other information to
assist your service technician in making repairs. Al-
though your vehicle will usually be drivable and not
need towing, see your authorized dealer for service as
soon as possible.
CAUTION!
• Prolonged driving with the MIL on could cause
further damage to the emission control system. It
could also affect fuel economy and drivability. The
vehicle must be serviced before any emissions
tests can be performed.
• If the MIL is flashing, severe catalytic converter
damage and power loss will soon occur. Immedi-
ate service is required.
Loose Fuel Filler Cap Message
If the vehicle’s diagnostic system determines that the fuel
filler cap in loose, improperly installed, or damaged, a
GASCAP message will be displayed in the instrument
cluster. Tighten the gas cap until a “clicking” sound is
heard. This is an indication that the gas cap is properly
tightened. Press the odometer reset button to turn the
message off. If the problem persists, the message will
428 MAINTAINING YOUR VEHICLE