P20E7Reductant Injection Air Pressure Too High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- On air-assisted DEF dosing the control unit regulates the compressed air fed into the mixing chamber so that the nozzle sprays a stable mist. P20E7 is set when the measured air pressure climbs above the permitted upper limit, for instance because the pressure control valve no longer throttles and passes full tank pressure, or because the path downstream of the sensor is narrowed so pressure builds up in front of it. Cummins bulletin TSB200096 shows how DEF crystals form in the air solenoid and the nozzle of air-assisted dosers, restricting flow and distorting the spray pattern. A skewed air pressure sensor gives the same reading. Airless systems in passenger cars do not have this circuit. No maker documents P20E7 publicly; CARB requires the air-assisted delivery to be monitored. Low pressure and leakage are P20E6 and P20CA.
- What you may notice
- Check engine light and SCR warning
- Irregular DEF spray, deposits in the exhaust and higher NOx
- Engine derate if dosing is shut down
- Likely causes
- LikelyAir pressure control valve no longer regulating and passing full supply pressure
- PossibleDEF crystals or deposits restricting the nozzle or mixing path
- PossibleAir pressure sensor reading too high
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.