P20F6 code meaning
Reductant Injection Valve Stuck Open (Bank 1 Unit 1)
Powertrain system Generic code P20xx codes Check engine light
What P20F6 means
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.
P20F6 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.3 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P20F6
- Check engine light and DEF warning
- Higher DEF consumption, white deposits in the exhaust or ammonia smell
- Dosing switched off and later inducement
Common causes of P20F6
- Most 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
- Less likelyLeaking or detached line at the valve imitating an open valve
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Reductant injection valve
What each part of P20F6 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 0 | Area: fuel and air metering and auxiliary emission controls. |
| F6 | The exact fault in that area. |
What to do next
- Note P20F6 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P20F6
What does P20F6 mean?
P20F6 means "Reductant Injection Valve Stuck Open (Bank 1 Unit 1)". Between pulses the dosing valve must seal tightly so DEF only enters the exhaust when commanded. It is a generic code, so it means the same on every make.
Is it safe to drive with P20F6?
Drive gently and only to a workshop. With P20F6 the car can go into limp mode (reduced power) to protect itself.
Will P20F6 fail an emissions test?
Yes, it can. P20F6 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P20F6 to fix?
Difficulty: medium. A typical repair takes 0.3 to 2.5 hours of work. This is a job for a workshop.
Will P20F6 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.