Service DEF System - XX miles until 65 mph

swaptrex14 · October 30, 2020

Woke up to this message this morning. Anything I can do without taking it to the dealer? The DEF tank is full (filled it up this morning hoping it would get rid of the message). Also, have a check engine light and what appears to be a DEF light. Truck has 2780 miles. Thanks in advance.

doozer78 · October 30, 2020

Woke up to this message this morning. Anything I can do without taking it to the dealer? The DEF tank is full (filled it up this morning hoping it would get rid of the message). Also, have a check engine light and what appears to be a DEF light. Truck has 2780 miles. Thanks in advance.

If the level gets too low you will get that warning message. I had same issue but only because on my way home from getting the truck the hose came off and I lost most of my fluid. Once I got hose reattached and filled up the def tank it took a little while before the message went away. It has to log a certain amount of miles/time before the message will go off

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doozer78 · October 30, 2020

Woke up to this message this morning. Anything I can do without taking it to the dealer? The DEF tank is full (filled it up this morning hoping it would get rid of the message). Also, have a check engine light and what appears to be a DEF light. Truck has 2780 miles. Thanks in advance.

Here is what I had

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doozer78 · October 30, 2020

Here is what I had

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Only reason I got the service message was the hose came off and couldn't spray the fluid into exhaust

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swaptrex14 · October 30, 2020

6 minutes ago, doozer78 said:

Only reason I got the service message was the hose came off and couldn't spray the fluid into exhaust

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Thanks. I don’t see any loose hoses but that sounds right. I really don’t want to take it to the dealer.

doozer78 · October 30, 2020

Thanks. I don’t see any loose hoses but that sounds right. I really don’t want to take it to the dealer.

My hose was completely off. Sprayed the fluid all over the undercarriage of truck I was pissed. Once I attached it and filled it up it took a few days before message went away but it's not a daily driver for me either so if you drive it often it may go away quicker. I'd wait it out

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swaptrex14 · October 30, 2020

59 minutes ago, doozer78 said:

My hose was completely off. Sprayed the fluid all over the undercarriage of truck I was pissed. Once I attached it and filled it up it took a few days before message went away but it's not a daily driver for me either so if you drive it often it may go away quicker. I'd wait it out

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Unfortunately I don’t see any fluid below but I also don’t seem to hear the fluid entering the exhaust. Very odd.

redwngr · October 30, 2020

1 hour ago, doozer78 said:

If the level gets too low you will get that warning message. I had same issue but only because on my way home from getting the truck the hose came off and I lost most of my fluid. Once I got hose reattached and filled up the def tank it took a little while before the message went away. It has to log a certain amount of miles/time before the message will go off

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Low def level should get a message that def needs to be added.

Service def warning is an indication that something is wrong with the system.

Heater, pump, injector, def lines, etc -- and it knows it has fluid, but the NOx levels are not being reduced as expected.

swaptrex14 · October 31, 2020

The dealer looked at it, there was a recall regarding the issue (Software or something). They weren’t aware until they looked it up. However, the main reason I’m getting the message (according to them) is I have my mirrors off of the truck and unhooked obviously, because I’m color matching them. It did start right after I removed them, but thought it was just a coincidence. Who would think I plugged mirrors would throw a def code.

redwngr · November 1, 2020

The 6.6 Dmax is probably still using a temperature sensor in the passenger mirror for engine control.

The temp displayed in the radio is from a sensor behind the grill.

Leeforbes · November 13, 2021

I also got the same error this morning when I had changed my air filter. I had unplugged my map sensor to get the top of the airbox off and forgot to plug it back in. After I drove for about a mile in these identical error warnings appeared. I stopped and turned off my truck and then plugged it back in the map sensor connection. After restarting the error messages disappeared in the truck ran perfect.

aliveguy5 · January 8, 2022

Ever since I put that platinum blue DEF in my 2021 I get errors all the time and they just go away. I get bad DEF warnings, low mileage warnings, they all go away. From now on I'm only putting the cheapest and freshest DEF I can find in my truck.

bowtie2007 · January 21, 2022

I also got def quality warnings with blue platinum. Stopped using it and the messages haven't returned.

TeeMan · February 17, 2022

I got this same message two days ago. After reading this post, decided to take it to the dealer. Just got the call, and it’s the redaction pump, and sensor. Going to take about ten days to bring a new one in. My question is how long will the new one last? I’ve only got 24,000km on this truck.

Richard Mathern · February 19, 2022

It is the def tank def heater it goes to heck alot. Right now national back order list. I have 26k miles on mine and it is my first one going out. However there are 6 other truck at our local dealer (GMC) alone ahead of me for the same part. I have been told 1 month till part might get here on mine. 2 weeks in and out of those 6 trucks only 2 have gotten their part. Fyi under warranty and no truck for me to use as it says. None on the lot to buy! None to rent that I can pull construction trailer. I am doing my best with no truck to pull trailers and run a construction company. It is the only truck I have that can do that. Right now I am running my full frame off restored 1982 Chevy scottsdale. Not happy about using that to haul stuff around. I just got that truck done a year ago.