P203B code 500 miles in

[HighTechPauper]

Just as a data point, my DIC shows DEF 2 bars down, but the Banks shows 65%, so DIC is not calibrated to actual level very well, it has always been like that, I will be in the 30's on the Banks before I see the DIC drop to half. I would caution adding anything to the DEF, I would also caution using the Blue Platinum, get fresh from Wally World or maybe at the pump and don't worry about it, I have had a load of DEF for 8 months before, still showed 32% and never have I had 1 emissions issue in either truck so far (knock on wood). As one last data point, I will occasionally see the DEF drop to as low as 28%, still never an issue and it comes back up to 32% without adding any or doing anything, I just drive it. I also have JUST 10K miles on the new one in 15 months, so I don't drive a lot, I'm retired and in this economy I don't waste money I may need later.

 

[AXE]

I run trucks in

Mine has always bounced around, I monitor DEF level, concentration, and DEF temperature. I often can start bouncing to 0 on a hill or bumpy roads, and I have read that frozen DEF can show as 0 on the iDash presumably because when frozen it loses its conductivity that the sensor uses to gauge the level. This is my second truck (21/RST/LM2 21.5K at trade and my 24/ZR2/LZ0/10K) that I have had the iDash on, both bounce around a bit but have never stayed at 0 but I don't know if I looked when I suspected my DEF was frozen. In IL I would imagine the DEF may be frozen solid this time of year and I think I remembered reading that the system will wait up to 30 minutes to thaw the DEF enough to be able to start injecting, if it can't by then it sets the CEL/MIL due to it, any chance freezing is the issue? Do you monitor DEF Temp too?
IMHO/YMMV

I've ran a few different DEF rigs in below 0 temps. Got many friends that live there and never seen a frozen DEF tank. So they either thaw quickly or there's some sort of override in the system for extreme cold.

 

[Grinks22]

Thanks for the information. Everything you said makes sense. I think I’m going to let it ride and see what happens. It’s crazy that the sensors and electronics are as imperfect as they are when Tesla can make a robot that washes a vehicle perfectly and a car that mostly drives itself lol.

 

[LSnTX]

I’m monitoring the DEF_L gauge. Don’t know the difference either.



All that DEF additive crap is snake oil.
If you go through it by towing or just driving a lot you’ll keep it fresh by just filling up.
I don’t go through a lot when I’m local, so my technique is just put in 1 to 1 1/2 gallons to keep it fresh. Like @HighTechPauper says, just drive it and don’t sweat that part.

 

[AXE]

Thanks for the information. Everything you said makes sense. I think I’m going to let it ride and see what happens. It’s crazy that the sensors and electronics are as imperfect as they are when Tesla can make a robot that washes a vehicle perfectly and a car that mostly drives itself lol.

Poor electronic parts and software is a majority of the problems we see posted on this forum.

I have had same DEF in my truck for several months without problems in the last 10+ years. I finally decided that since I wasn't doing as many miles, a 2.5 gallon jug was enough when close to empty so it would stay fresh.

Get your DEF at Walmart or a busy truck stop and it'll be fresh because turnover is high.