165 miles unitl 65 mph

[gator63]

2012 Sierra Duramax/64000 miles, A check engine light came on and the message 165 mile until 65 mph was displayed, then the Service emissions system came on and check owners manual. Thought it may be the DEF fluid, so i bought some and added 5 gals worth(Warning light for DEF never came on).

Once fluid was added the check engine light went away but message still appears, can't check anything in the DIC because it won't let me. Question is how or when will the message disappear?

[Hillwood]

2012 Sierra Duramax/64000 miles, A check engine light came on and the message 165 mile until 65 mph was displayed, then the Service emissions system came on and check owners manual. Thought it may be the DEF fluid, so i bought some and added 5 gals worth(Warning light for DEF never came on).
Once fluid was added the check engine light went away but message still appears, can't check anything in the DIC because it won't let me. Question is how or when will the message disappear?

You need a scan tool that is able to perform the resets . Reductant system malfunction service bay test ... You should pull codes too and verify that there is not a fault in the system.

Sent from my SM-G965U using Tapatalk