NHTSA Service Bulletin 10190380: 2010-2016 Chevrolet Express

Information on Diesel Exhaust Fluid (DEF) Filling Instructions, Frozen Tank Status and General Information In operating temperatures of 15F (−9C) or less, customers may comment on an Exhaust Fluid Range message displaying on the DIC even though the DEF fluid has been filled. When the DEF is frozen, the level sensor cannot determine the fluid level in the tank. If this occurs the logic of the PCM will assume a default fluid level. The logic will use the calculated range based on DEF dosing history and the assumed fluid level. If there is a high learned dosing rate and the fluid has not thawed to where the pins of the level sensor can function, there is a possibility the Exhaust Fluid Range message can set with the range from approximately 1609 km (1000 mi) to less than 482 km (300 mi), even though the tank is known to have fluid or be full. This is an operating characteristic of the system. However to increase or eliminate the range message, once the range drops below 482 km (300 mi), the DEF tank should be refilled. This should allow refill detection to occur and turn off the range indicator. The operator must be sure not to overfill the DEF tank using the instructions provided in this bulletin or in the owners manual. When in frozen tank status, refill detections are not allowed until the warning strategy reaches the point at which the distance remaining is less than 482 km (300 mi). The refill detection is dependent on the DEF thawing enough that the level sensor pins can be read. A fully frozen tank can take almost an hour to detect a refill, after the vehicle is started. This condition should not be confused with the situation described in PIP4864: Low Or Speed Limited Diesel Exhaust Fluid Message (DEF) Will Not Reset.