P20F6Reductant Injection Valve Stuck Open (Bank 1 Unit 1)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Between pulses the dosing valve must seal tightly so DEF only enters the exhaust when commanded. P20F6 means the control unit concluded that the first valve on bank 1 stays open: the pressure collapses, or the pump has to work much harder to hold it than the commanded quantity explains. A Cummins patent describes this kind of check, comparing the measured pump effort with the expected flow; a strongly negative error points to a stuck-open valve, a leak or a disconnected line. FCA lists P20F6 for the Jeep Compass with the 2.0 L diesel (sales code EBS) in bulletins 18-034-20, 18-008-23 and 18-026-23 and cures it with control unit software; one case comes with system and DCU supply voltage too high. Overdosing risks ammonia slip and deposits. The stuck-closed counterpart is P208E, bank 2 is P20F7.
- What you may notice
- Check engine light and DEF warning
- Higher DEF consumption, white deposits in the exhaust or ammonia smell
- Dosing switched off and later inducement
- Likely causes
- LikelyCrystals or debris on the valve seat keeping the valve from closing
- PossibleMechanically sticking or heat-damaged dosing valve
- PossibleControl unit software misjudging valve closure, cured by an update
- RareLeaking or detached line at the valve imitating an open valve
- 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: €0 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.