There are four different messages which are displayed if the vehicle detects that the DEF system has been filled with a fluid other than DEF, has experienced component failures, or when tampering has been detected. The vehicle may be limited to a maximum speed of 5 mph (8 km/h) if the DEF system is not serviced within less than 200 miles (322 km) of the fault being detected.
When the DEF system needs to be serviced the following warnings will display:
DEF Low Refill Soon — This message will display when the low level is reached, during vehicle start-up, and with increased frequency during vehicle operation. It will be accompanied by a single chime. Approximately 5 gallons (19 Liters) of DEF is required to refill the tank when this message is initially displayed. on pickup applications, and approximately 7 gallons (26 Liters) are required on chassis-cab applications.
Speed Limited to 5 MPH in XXX mi Refill DEF — This message will continuously display if the “DEF Low Refill Soon” message is ignored, and the frequency of occurrence of the chime will increase unless up to 2 gallons (7.5 Liters) of DEF is added to the tank.
5 MPH Max Speed on Restart, Long Idle or Refuel Refill DEF — This message will continuously display when the counter reaches zero, and will be accompanied by a periodic chime.
The vehicle will only be capable of a maximum speed of 5 mph upon the first of the following conditions to occur:
If the vehicle is shut off and restarted.
If the vehicle is idled for an extended period of time, approximately one hour or greater.
If the system detects that the level of fuel in the tank has increased.
Add a minimum of 2 gallons (7.5 Liters) of DEF to the tank in order to avoid vehicle operation at a maximum speed of 5 mph (8 km/h).
A minimum of 2 gallons (7.5 Liters) may be required to restore normal vehicle operation. Although the vehicle will start normally and can be placed in gear after this message has been initially displayed, extreme caution should be utilized since the vehicle will only be capable of maneuvering at a maximum speed of 5 mph (8 km/h).