Easily check the freshness of your Diesel Exhaust Fluid (DEF) with Blue Def Decoder.
Enter the 5–11 character code printed on your DEF container — whether it’s the short date section or the full code — and instantly see the manufacturing date and freshness status.

Use Blue Def Decoder to:

Confirm your DEF hasn’t expired
Track shelf life for storage
Verify compliance for your vehicle

Blue Def Decoder saves you time and removes the guesswork from DEF code verification. Perfect for Sprinter van owners, diesel truck drivers, and anyone who needs quick, accurate results.