Dodge 2015 RAM Owner's Manual page 202

200 UNDERSTANDING YOUR INSTRUMENT PANEL
When the DEF system needs to be serviced the following
warnings will display:
• Service DEF System See Dealer — This message will
display when the fault is initially detected, each time
the vehicle is started, and periodically during driving.
The message will be accompanied by a single chime.
We recommend you drive to your nearest authorized
dealer and have your vehicle serviced as soon as
possible.
• 5 MPH Max Speed in 150 mi Service DEF System See
Dealer — This message will display if the DEF system
has not been serviced after the "Service DEF System –
See Dealer" message is displayed. This message will
continuously display until the mileage counter reaches
zero, and will be accompanied by a periodic chime.
The message will continue to countdown until it
reaches zero unless the vehicle is serviced. We recom-
mend you drive to your nearest authorized dealer and
have your vehicle serviced immediately.
NOTE: Under some circumstances this mileage counter
may start with a value of less than 150 miles (241 km). For
example, if recurring faults are detected in a time interval
of less than 40 hours, the counter may restart at the value
where it stopped when a previous fault was temporarily
remedied, or at a minimum of 50 miles (80 km).
• 5 MPH Max Speed on Restart, Long Idle or Refuel
Service DEF See Dealer — This message will continu-
ously display when the mileage counter reaches zero,
and will be accompanied by a periodic chime.