white powder in exhaust pipe and P205C CEL

[elgo]

I have a 2011 Sprinter (2012 AI with 39k miles) and the CEL came on. There is no DEF light and the CEL is not flashing. No countdown (yet). Scanner suggests P205C issue (heat sensor in DEF tank). History showed P205B codes (also heat sensor). I am traveling in Albuquerque, and if this is just an issue related to heating the DEF fluid above freezing levels, I would prefer to drive home to CA where any work will be warranty for a year. I also noticed white powder (like baking soda) inside exhaust pipe). Also, the DEF seems to be consumed at high levels.

Properly thawing DEF isn't an issue on this trip as I'm not in freezing temps, but does the high consumption rate of DEF or white powder point to larger issues I need to be concerned about? I am out of warranty except for EGR valve which has a 10 year warranty, so hoping that this is a related to EGR...

[primepower]

Definitely points to the DEF. My guess would be the DEF injector is leaking.

[BayouBiker]

There is some limited information on some truck forums about this. Summary:

1. Partially plugged Injector could be the issue - remove it and clean it with warm fresh water
2. Gen 12 and earlier systems can experience DEF injection runaway due to the NOX sensor interpreting excessive Ammonia (DEF is Urea which is converted to Amonia and then reduces NOX back to N2) as NOX. Newer systems add a Urea detector. Older systems require a software fix and system reset to reduce this issue once it gets started.

[elgo]

Thanks for the replies. I'm at a Silverstar Autohaus in ABQ and they have indicated that it is a faulty pressure sensor for DEF.

[elgo]

The error code says there is a short circuit to ground in pressure sensor.

[BayouBiker]

Well there you go! It's nice when the computer will tell you what's wrong.

[elgo]

Originally Posted by BayouBiker

Well there you go! It's nice when the computer will tell you what's wrong.

These guys are telling me that the Sprinter DEF related components are frequent problems (pumps, NOX sensors, heat sensors, etc). Everytime it requires a fix is going to run $2000. Good thing you are still in warranty - mine choose to break a few months after my warranty expired. I'm looking into a scanner now.