OBD-II code · Powertrain (generic, extended)
P20E6 Reductant Injection Air Pressure Too Low
The DEF system air-assist pressure is below the required threshold — pump weak, line leak, or pressure-control valve stuck open.
Is it safe to drive with P20E6?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyAir pump weak
- PossibleLeak in air line
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
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.7–3 h
- Emissions test
- Likely to fail
- Parts involved
- Reductant Air Pump, Reductant Air Pressure Control Valve, Reductant Air Line
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.