Dodge 2004 Ram Pickup 1500 - Manual (Page 326)

b. The MIL light will remain fully illuminated until the
first engine crank or the key is turned off. This means
that your vehicle’s OBD system is ready and you can
proceed to the I/M station.
If your OBD system is not ready, you should see your
dealer or repair facility. If your vehicle was recently
serviced or had a battery failure or replacement, you may
need to do nothing more than drive your vehicle as you
normally would in order for your OBD system to update.
A recheck with the above test routine may then indicate
that the system is now ready.
Regardless of whether your vehicle’s OBD system is
ready or not ready, if the MIL symbol is illuminated
during normal vehicle operation, you should have your
vehicle serviced before going to the I/M station. The I/M
station can fail your vehicle because the MIL symbol is on
with the engine running.
DEALER SERVICE
Your dealer has the qualified service personnel, special
tools and equipment to perform all service operations in
an expert manner. Service manuals are available which
include detailed service information for your vehicle.
Refer to these manuals before attempting any procedure
yourself.
NOTE: Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
326 MAINTAINING YOUR VEHICLE