DEF Fault Codes - P2003A or 004BAC - when tanks are pretty full

[josiahg52]

I read your post again. You're getting a CEL and a DTC? That's not indicative of low urea level at all. Ard and I are speaking of the Low DEF "No Start in 999 Miles" warning that comes on in the instrument cluster and on the iDrive display. The P203/04BAC DTCs specifically concerns the reductant level detection system for the active tank which means there could an issue with the level sensors.


BMW NA extended the warranty on the active tank under SI B 01-23-16 to 10 years/120,000 miles. There is also an extended warranty for several other NOx reduction system components.


I had them all replaced in 2016 when I got the 04BAC DTC and it could not be cleared due to the level sensors in the active tank being faulty.

[FunfDreisig]

Originally Posted by josiahg52

...BMW NA extended the warranty on the active tank under SI B 01-23-16 to 10 years/120,000 miles. There is also an extended warranty for several other NOx reduction system components.

Thanks for the heads up.

The CEL/DTC with 004BAC came back on last week. The dealer replaced the Active DEF tank under the 10yr extended warranty with no drama

Funf Dreisig