DEF Gauge Inaccurate

[Ltngdrvr]

Well... My 19' threw a code and went to countdown cause I overfilled it... Guess Y'all are lucky.

https://www.turbodieselregister.com/threads/code-p203e-service-def-system-message.269553/

P203E - Reductant (DEF) Level Sensor Circuit Intermittent/Erratic

It wasn't because you overfilled it, that code was due to some other fault with the level sensor.

 

[Cummins12V98]

Normal driving at 1/2 tank I add 2.5. On “E” I have added two 2.5’s. Towing at truck stops I fill to the very top like I always do with Diesel. Knock on wood never an issue.

must have the special truck, don’t even have the dead pedal with the AISIN. ​

 

[gsbrockman]

I’ve filled my 2018 RAM 4500 with DEF till it runs out of the filler neck.....and nary a problem, through 294k miles.

 

[R.Taylor]

It wasn't because you overfilled it, that code was due to some other fault with the level sensor.

Never ever ever had a problem in 11k miles then I overfilled it and it gave an error..... I drained some off and it went away. No problem since and I'm at 15k now and no sensor error has come back.

Don't over fill aka top off the DEF.... It can cause a code to be thrown. Ltngdrvr.... Your truck is a 15' and mines a 19' meaning there may be differences in monitored parameters.

 

[Ltngdrvr]

Never ever ever had a problem in 11k miles then I overfilled it and it gave an error..... I drained some off and it went away. No problem since and I'm at 15k now and no sensor error has come back.

Don't over fill aka top off the DEF.... It can cause a code to be thrown. Ltngdrvr.... Your truck is a 15' and mines a 19' meaning there may be differences in monitored parameters.

Nah, still don't think that was your issue, just coincidence.
Myself, as well as many others fill to the top with no issues, and AFAIK, no changes have been made to the DEF tank on newer trucks.

 

[sag2]

STAR case explains it.

Symptom/Vehicle Issue: Malfunction Indicator Lamp Illumination (MIL). Diagnostic Trouble Code (DTC) P203E – Reductant Level Sensor 1 Circuit Intermittent-Erratic Set.
Discussion: Some customers may experience a MIL illumination. Upon further investigation, a technician may find DTC P203E set in the Powertrain Control Module (PCM) memory.
If you receive a vehicle with this DTC, check to see if the DEF tank was just recently filled prior to the DTC setting. P203E will set if the tank is overfilled resulting in no air space above the DEF Fluid in the tank.
The DEF level sensor is new for 2019 Model Year, and uses an ultrasonic frequency signal to detect fluid level. Previous model years use a radio frequency type sensor which acts differently. The air space above the fluid is crucial to bounce back the UF signals back to the new sensor for proper level detection.
If you suspect that the tank might be overfilled, drain 2-3 gallons of fluid from the tank. Once drained, you will need to perform a specific drive cycle to clear the message, and ensure the vehicle is repaired.

 

[Wiredawg]

Is overfilling the same as topping off or filling until it spills out? I'm thinking the latter. DEF is nasty and you don't want to spill it. Not sure how the truck would know if its topped off as there is no sensor in the fill tube or the upper part of the tank that I've seen. Another consideration for not filling to the top besides freezing is expansion with heat, unless traveling with it.

EDIT: Just read SAG2 post above that mentions a senior on the 19+ trucks that explains the code.

I've only filled mine at a truck stop pump a couple times and I stop when it clicks the first time, same as everything.

My DEF gauge works OK and haven't had problems with it. Mine holds 9 gallons, but gauge shows half full, but that's about 2.5 gallons. I guess they REALLY dont want you to run out of DEF.

Interesting thread though.



Cheers, Ron

 

[gsbrockman]

Is overfilling the same as topping off or filling until it spills out? I'm thinking the latter. DEF is nasty and you don't want to spill it. Not sure how the truck would know if its topped off as there is no sensor in the fill tube or the upper part of the tank that I've seen. Another consideration for not filling to the top besides freezing is expansion with heat, unless traveling with it.

EDIT: Just read SAG2 post above that mentions a senior on the 19+ trucks that explains the code.

I've only filled mine at a truck stop pump a couple times and I stop when it clicks the first time, same as everything.

My DEF gauge works OK and haven't had problems with it. Mine holds 9 gallons, but gauge shows half full, but that's about 2.5 gallons. I guess they REALLY dont want you to run out of DEF.

Interesting thread though.



Cheers, Ron

To add to this.....
The breather / vent for the 2018 and down DEF tank on a Cab and Chassis is actually tied in to the filler neck itself, verrrrrry close to where the cap attaches. It would be interesting to see if the 2019 & up Cab and Chassis are similar in design in relation to the breather.

 

[Ltngdrvr]

STAR case explains it.

Symptom/Vehicle Issue: Malfunction Indicator Lamp Illumination (MIL). Diagnostic Trouble Code (DTC) P203E – Reductant Level Sensor 1 Circuit Intermittent-Erratic Set.
Discussion: Some customers may experience a MIL illumination. Upon further investigation, a technician may find DTC P203E set in the Powertrain Control Module (PCM) memory.
If you receive a vehicle with this DTC, check to see if the DEF tank was just recently filled prior to the DTC setting. P203E will set if the tank is overfilled resulting in no air space above the DEF Fluid in the tank.
The DEF level sensor is new for 2019 Model Year, and uses an ultrasonic frequency signal to detect fluid level. Previous model years use a radio frequency type sensor which acts differently. The air space above the fluid is crucial to bounce back the UF signals back to the new sensor for proper level detection.
If you suspect that the tank might be overfilled, drain 2-3 gallons of fluid from the tank. Once drained, you will need to perform a specific drive cycle to clear the message, and ensure the vehicle is repaired.

Well, that sucks for 19+ owners then, and would bother the hell out of me. Plus, how would you know you overfilled until it tripped the CEL???
But, it also sounds like it would reset itself after the truck was driven far enough for the level to drop on its own and a few restarts are performed.

 

[sag2]

I have to think that by overfill they are trying to get every last drop into the tank. I have only filled my tank completely a couple times in 32k. I run it down and then add 2 1/2 gallons. There really is no need to fill it unless you are towing hard every day for a living and don't want to be messing with it every few days.

 

[Ltngdrvr]

I have to think that by overfill they are trying to get every last drop into the tank. I have only filled my tank completely a couple times in 32k. I run it down and then add 2 1/2 gallons. There really is no need to fill it unless you are towing hard every day for a living and don't want to be messing with it every few days.

I use a tankful or more of DEF almost every week, only time I don't is when I'm not working.
Would suit me no end if the tank on pickups was the same size as C&C trucks.
And, I hardly ever buy jugs, way too inconvenient, so much more convenient to just fill at the pump when fueling.

 

[bcbender]

've only filled mine at a truck stop pump a couple times and I stop when it clicks the first time, same as everything.

Well, I am going to just try to keep this protocal and hope there is enough airspace left after the first "click" to keep it happy. I too dont want to deal with finding and filling more frequently if it is not absolutely necessary.

 

[Wiredawg]

Well, I am going to just try to keep this protocal and hope there is enough airspace left after the first "click" to keep it happy. I too dont want to deal with finding and filling more frequently if it is not absolutely necessary.

BC,

If the one click doesn't work, you may figure out the quantity to add based upon the gauge reading... mine is 2.5 gallons at the half mark and 5 gallons at the top of the red mark, so for me worst case is a 4 gallon reserve.

It's interesting hearing how Ram changes sensors and technology on a system and why.

Another quirk, at least for me, is the failure of the forums to label the 19+ trucks 5th Gens, different motors, new facia, upgraded systems. Even Cumins went back and removed wording about thier motors in the next generation Rams. Wonder what that's going to take to happen?

Anhoo, nice truck and good luck having a long trouble free experience.

Cheers, Ron

 

[AH64ID]

Another quirk, at least for me, is the failure of the forums to label the 19+ trucks 5th Gens, different motors, new facia, upgraded systems. Even Cumins went back and removed wording about thier motors in the next generation Rams. Wonder what that's going to take to happen?

Anhoo, nice truck and good luck having a long trouble free experience.

Cheers, Ron

But they aren’t a 5th Gen. The changes were relatively minor. Realistically not much different than a 05 to a 07, yet those were all 3rd gens.

Major frame and emissions changes in 13/14, same gen.

So it’s more than facia, headlights, emissions, and motor stuff. It’s a major change and that didn’t happen in 19.

 

[bcbender]

Thanks Ron... I really love the new truck every day even more. I thought I would miss my 6spd but these new trucks make long trips just melt away.

I assume since there are still a lot of common components they still call em 4.5 GEN? similar to the 07-09s? I don't know but there are a lot of differences as you pointed out and I am learning with regards to many things under the skin. And other that cost I cannot understand either why you would change to unproven technology but it is FCA and the way things go.... (Furd and Chevy are not any better tho)

 

[Wiredawg]

Thanks Ron... I really love the new truck every day even more. I thought I would miss my 6spd but these new trucks make long trips just melt away.

I assume since there are still a lot of common components they still call em 4.5 GEN? similar to the 07-09s? I don't know but there are a lot of differences as you pointed out and I am learning with regards to many things under the skin. And other that cost I cannot understand either why you would change to unproven technology but it is FCA and the way things go.... (Furd and Chevy are not any better tho)

Any designation to differentiate them would be nice... 4.5, 4.25, etc

I know following past posts, if Ram could have figured a way to deliver a flat floor like our '19 Ram 1500, might've made it. Could be other reasons like bigger trans and/or xfer cases prevent making it work.

Anyhoo, I guess we'll see what Ram comes up with to actually qualify as 5th Gen.

Cheers, Ron