[boom]

So I have a persistent CEL: 004804 DDE Reducing agent pressure buildup, plausibility.

Found this but no resolution.
http://www.bimmerfest.com/forums/sho...d.php?t=655644

I've already replaced a DEF tank and am tired of spending money to fix a system that is unnecessary, problematic, and costly to repair. I have read a bunch of threads about tuning and deleting the SCR and EGR systems and looking for information on a fully sorted setup. I'm prepared to by the downpipe and tune, and I'm looking for the complete package that will allow the OBDII diesel emissions check pass.

Thanks in advance.

[BB_cuda]

Link is no longer any good.

I'm wondering if pressure buildup means that the metering valve (that's the urea injector) is clogged and needs cleaning with distilled water.

[boom]

Originally Posted by BB_cuda

Link is no longer any good.

I'm wondering if pressure buildup means that the metering valve (that's the urea injector) is clogged and needs cleaning with distilled water.

Yeah, I forgot that bimmerpost deletes the information from competing forums. Pretty crappy policy if you're trying to share information... Anyway, I first thought it was the injector but that link says the pump can't develop pressure so it may be the pump. It's $500-600 and a bunch of labor which is why I'm considering deleting the system. I might try adding some hydrochloric acid to see if I can get the the crystallized stuff to dissolve if that's the issue.

[fsd350]

Originally Posted by boom

So I have a persistent CEL: 004804 DDE Reducing agent pressure buildup, plausibility.

Found this but no resolution.
http://www.bimmerfest.com/forums/sho...d.php?t=655644

I've already replaced a DEF tank and am tired of spending money to fix a system that is unnecessary, problematic, and costly to repair. I have read a bunch of threads about tuning and deleting the SCR and EGR systems and looking for information on a fully sorted setup. I'm prepared to by the downpipe and tune, and I'm looking for the complete package that will allow the OBDII diesel emissions check pass.

Thanks in advance.

I used BPC on my X5 35d- bimmerperformancecenter.com in NC. They are great to deal with. Advisor is Randall Tuner is Bob. Bob posts here frequently

I used JR Auto Performance and Bohl for my 335d. Great option as well

I believe AA Rodriguez is a US option for the JR Auto Tune and supplies DP's. He posts here frequently also.

All have threads on this board

If you want to pass emissions, better keep all your hardware for recurring tests. If checking OBDII readiness only, they can tune around that I believe. There are others on here that have much more knowledge than I.

[Doug Huffman]

Originally Posted by boom

I might try adding some hydrochloric acid to see if I can get the the crystallized stuff to dissolve if that's the issue.

That is not the issue. Urea is more than 100 w/w soluble in 20C water. 4000 g/liter water 80C.

[BB_cuda]

Doug, you have come over to the dark side. Welcome :-).
I agree. Do not use acid to clean this. Water will be fine.

[Bob@BPC]

Originally Posted by BB_cuda

Doug, you have come over to the dark side. Welcome :-).
I agree. Do not use acid to clean this. Water will be fine.

+1

[fsd350]

+2 dissolves easily on contact with water. Be sure to use distilled water only and be very meticulous to prevent contamination of the system