Diesel Exhaust Fluid (DEF)
Critical For OperationEmissions System
Reduces nitrogen oxide (NOx) emissions in diesel engines.
Diesel Exhaust Fluid (DEF) is a urea-based fluid injected into the exhaust system of diesel engines to convert nitrogen oxides (NOx) into nitrogen and water, reducing emissions.
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Typical part cost
$10–$30🔒
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DIY difficulty
2/10
⚠️ Owners Often Notice
If the Diesel Exhaust Fluid (DEF) is starting to fail, these are the signs owners most commonly report before it gets worse:
Emission warning light
Reduced engine power
Failed emissions test
Poor fuel economy
Poor DEF system performance
Exhaust smell
Related Services
Services commonly performed on or around this part.
Add Diesel Exhaust Fluid (DEF)
No standard interval on file
DEF System Service
No standard interval on file
Flush Diesel Exhaust Fluid (DEF)
No standard interval on file