Case 621F DEF code 3350

[Gene Allar]

I just purchased a new-to-me 2013 Case 621F Wheel loader. We need to drive the unit 9 miles from our shop to the places we use the loader to plow snow. It seems like anytime we get above 1700rpm the yellow caution comes on referring to code 3350, Termin50 sig. Wrong operation. It also notes DEF/Ad/blue injection failed, torque limited. If we shout down the unit for a bit and restart, the caution remains but the engine will operate good up to about 1700rpm. Again if we go past the 1700, next the red stop will appear cutting power. Our dealer isn't coming up with a fix yet. They tested the DEF fluid and found it only at 30% so we drained the tank and refilled with new DEF. We changed the knock sensor since it came up as an issue on their computer. Same problem after both adjustments. Any help would be greatly appreciated.

 

[Coy Lancaster]

You either have the DEF injection module or the injector bad I'm thinking. Unfortunately you will need to get service tech to put computer on machine to make for sure.