Warning message DEF poor quality after 100 miles speed will be limited to 65 mph.

[Koop]

Anyone know what is causing this.  The DEF is full truck has 71,000 miles.  Already replaced a NOx sensor today that had a code showing?  Any thoughts on how to get ride of the message and solve the issue causing it?

[newdude]

Dealer needs to do a service bay tampering test which may or may not lead to them doing a commanded regen.  

 

Can't just put in a NOX sensor and clear the code(s) or put it in and expect it to go away.  

Edited August 5, 2022 by newdude

[bshort]

When this happened to me, I added fresh DEF and the message went away.  Since you're full, pump some out and add fresh DEF. 

[newdude]

22 hours ago, bshort said:

When this happened to me, I added fresh DEF and the message went away.  Since you're full, pump some out and add fresh DEF. 

 

 

OP posted this August 3 2022.  Its now August 25th 2023 as I type this.  

 

Also, he stated he just replaced the NOx sensor which had a code for it.  You cannot just clear those codes out.  There are tests within the ECM that have to be done to reset the diesel emissions components.  

 

A code for the NOx sensor wouldn't be fixed by siphoning the DEF tank and adding new DEF.  

Edited August 25, 2023 by newdude

[bshort]

49 minutes ago, newdude said:

 

 

OP posted this August 3 2022.  Its now August 25th 2023 as I type this.  

 

Also, he stated he just replaced the NOx sensor which had a code for it.  You cannot just clear those codes out.  There are tests within the ECM that have to be done to reset the diesel emissions components.  

 

A code for the NOx sensor wouldn't be fixed by siphoning the DEF tank and adding new DEF.  

I see.  Without the code, my issue (same as title) was resolved with fresh def.