OBD-II code · Powertrain (generic, extended)
P20F5 Reductant Consumption Too High
The DEF consumption observed over the dosing window is above the model expectation — typically a leaking injector seat, leaking line fitting, or a pressure-control valve that vents constantly to the tank.
Is it safe to drive with P20F5?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelyInjector seat leaks DEF into exhaust
- PossibleCracked line or fitting
Symptoms
- Check engine light or NOx warning on
- AdBlue/DEF level or quality warning
- Possible no-start countdown after ignore period
- Failed emissions inspection (NOx)
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–4 h
- Emissions test
- Likely to fail
- Parts involved
- Reductant Injection Valve, Reductant Supply Line, Reductant Pressure Control Valve
Related codes
- P20F4Reductant Consumption Too Low
- P20F2SCR NOx Catalyst Efficiency Below Threshold (Bank 2)
- P20F3SCR NOx Pre-Catalyst Efficiency Below Threshold (Bank 2)
- P20F6Reductant Injection Valve Stuck Open (Bank 1 Unit 1)
- P20F7Reductant Injection Valve Stuck Open (Bank 2 Unit 1)
- P20F8Intake Manifold Runner Control Circuit Performance (Bank 1)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.