Theory Of Operation

WARNING: This page is about a different car, the 2017 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

The Diesel Exhaust Fluid (DEF) system holds a total of 5.7 gallons of fluid on a regular cab and 9.2 gallons of fluid on a chassis cab vehicle. There are a series of three warning levels to indicate to the customer when the fluid is low or incorrect. The driver warning and inducement strategy for a low fluid condition is as follows: The first warning will occur when the tank level is at approximately two gallons. The customer will hear a chime and get an EVIC message reading "DEF Low REFILL Soon". The second warning level will occur when the tank level is at approximately 1.5 gallons. The customer will hear a chime and get an EVIC message reading "Speed Limited to 5 mph in XXX MILES Refill DEF". The customer will hear a chime and get an EVIC message reading "5 mph Max Speed Refill DEF". The system will arrive at this level with approximately 0.7 gallon of fluid left in the tank. A minimum of two and a half gallons of approved Diesel Exhaust Fluid is added to the tank to eliminate the 5mph derate. .