2025 Cummins--Anyone notice that DEF gauge not reading correctly?

[MacksRam]

I have a 2025 3500 cab and chassis. I have experienced the def gage problem also have had the flash done but didn’t help taking it back Friday. Mine will range from full to saying it will go in limp mode in 200 miles in just a few miles of driving will keep posted on what happens.

Yes, keep us posted as to what part fixes it.. The initial flash they did not help my erratic DEF gauge either.

(Honestly, I don't think Ram has a clear plan as to exactly what the fix is---seems like they are throwing different parts on the trucks from the different dealerships. My Ram Service Advisor told me they opened a Star case at Ram--connected my truck to their computer--then the dealership MUST do and/or install whatever part Ram tells them---I am still driving my truck to see if the most recent part has fixed it--Diesel Exhaust Fluid Dosing Control Unit)

 

[ddt4x4]

My last update was the dealer dealer replaced the pump. After a few weeks the issue came back. The dealer said there is a bulletin to upgrade the software it was fine for a week. Today I dropped it off again because this weekend it was at 3/4 of a tank then dropped to less than a 1/4 and alarmed then went into limp mode. When I shut it down and restarted the truck the DEF tank went to 1\2 full alarm cleared.
This morning on the way to the dealer it was at 1/2 tank and went to a 1/3. I noticed when I use the engine brake it fluctuated even more. The dealer just called and said it was another F#ck!&g Pump! I asked him what is the life span of a pump? We discussed it and now they are going to look for other potential causes. I think it's the sensor, but it is built into the tank. I also asked him to call RAM tech support and get help.

Very Frustrating

 

[MacksRam]

My last update was the dealer dealer replaced the pump. After a few weeks the issue came back. The dealer said there is a bulletin to upgrade the software it was fine for a week. Today I dropped it off again because this weekend it was at 3/4 of a tank then dropped to less than a 1/4 and alarmed then went into limp mode. When I shut it down and restarted the truck the DEF tank went to 1\2 full alarm cleared.
This morning on the way to the dealer it was at 1/2 tank and went to a 1/3. I noticed when I use the engine brake it fluctuated even more. The dealer just called and said it was another F#ck!&g Pump! I asked him what is the life span of a pump? We discussed it and now they are going to look for other potential causes. I think it's the sensor, but it is built into the tank. I also asked him to call RAM tech support and get help.

Very Frustrating

ddt4x4,
I understand your frustration!
Above you state: "I think it's the sensor, but it is built in the tank."---Which sensor are you referring to? Do you know the name of that sensor?

 

[ddt4x4]

ddt4x4,
I understand your frustration!
Above you state: "I think it's the sensor, but it is built in the tank."---Which sensor are you referring to? Do you know the name of that sensor?

The DEF sensor built into the tank. Which means they would have to replace the tank. In 2025 the DEF sensor is part of the tank instead of a separate component.

On the 2025 Ram 2500, the DEF (Diesel Exhaust Fluid) level sensor is integrated into the header assembly inside the DEF tank.

 

[timberjackrob]

Yes, keep us posted as to what part fixes it.. The initial flash they did not help my erratic DEF gauge either.

(Honestly, I don't think Ram has a clear plan as to exactly what the fix is---seems like they are throwing different parts on the trucks from the different dealerships. My Ram Service Advisor told me they opened a Star case at Ram--connected my truck to their computer--then the dealership MUST do and/or install whatever part Ram tells them---I am still driving my truck to see if the most recent part has fixed it--Diesel Exhaust Fluid Dosing Control Unit)

Took truck into dealership today they have decided to replace the tank. Which I understand has all the components sensor,sending unit,pump built in? However the tank is on back order will have to wait and see. Will post when tank gets installed.

 

[MacksRam]

Took truck into dealership today they have decided to replace the tank. Which I understand has all the components sensor,sending unit,pump built in? However the tank is on back order will have to wait and see. Will post when tank gets installed.

Yes, many of the components are built in the DEF tank, but not all components. For example, the Diesel Exhaust Fluid Dosing Control Unit is located on top of the tank. This control unit did NOT fix mine--I am working with Service now to carry my truck back in--this will be the 3rd Ram dealer appointment related to erratic DEF gauge reading. Please keep us updated on your progress....I will do the same...

 

[Plater]

I'm not sure this will help but I was looking up what the little nub on the bottom of my driver's side mirror was for because it was rusty I decided to try Goggle AI
and it said it was the AAT sensor, Ambient Air Temperature sensor it said it could trigger a Check engine light a DEF fault if it was bad.

 

[MacksRam]

I'm not sure this will help but I was looking up what the little nub on the bottom of my driver's side mirror was for because it was rusty I decided to try Goggle AI
and it said it was the AAT sensor, Ambient Air Temperature sensor it said it could trigger a Check engine light a DEF fault if it was bad.

Plater,
Can you post a picture of this "little nub on the bottom of driver mirror"? (As I cannot picture in my mind what you are talking about)

 

[timberjackrob]

I'm not sure this will help but I was looking up what the little nub on the bottom of my driver's side mirror was for because it was rusty I decided to try Goggle AI
and it said it was the AAT sensor, Ambient Air Temperature sensor it said it could trigger a Check engine light a DEF fault if it was bad.

I found it on mine never knew it was there it wasn’t rusty. It was located down toward the bottom of drivers side mirror on the front.

 

[MacksRam]

I found it on mine never knew it was there it wasn’t rusty. It was located down toward the bottom of drivers side mirror on the front.

I assume this is what you are talking about--see attached picture. What does it do? Again, it can trigger a check engine light that is related Diesel Exhaust Fluid (DEF)???