P22FF code meaning
SCR NOx Catalyst Inlet Temperature Too Low
Powertrain system Generic code P22xx codes Check engine light
What P22FF means
Diesel engines raise exhaust temperature on purpose so the SCR catalyst can reduce NOx; this code reports that the gas entering the SCR stays too cold despite that. Ford describes it for the 6.7L and 3.2L diesels under its monitoring of the exhaust temperature controller: the measured SCR inlet value is compared with the setpoint, and the fault sets when it lags more than 80 °C behind for 300 s (2015 model year, roughly 800-1600 rpm and 50-600 Nm, EGT and EGR inputs fault-free). Deutz EMR5 maps P22FF to SPN 4360 FMI 1, below the normal range. Volvo cut false P22FF settings with a 2021 engine software update (KC-589). P05EB covers cold starts, P214A the opposite case.
P22FF at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of P22FF
- Check engine light on
- Reduced NOx conversion, possible further SCR efficiency codes
- Code returns after extended idling
Common causes of P22FF
- Most likelyLong idling or light-load operation keeps exhaust cold
- PossibleExhaust leak ahead of the SCR cools the gas or skews the reading
- PossibleExhaust temperature sensor reading too low while still in range
- Less likelyEngine software with overly strict monitor (update available on some makes)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
SCR inlet temperature sensorSCR catalystExhaust heat management
What each part of P22FF means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 2 | Area: fuel and air metering (injector circuit). |
| FF | The exact fault in that area. |
What to do next
- Note P22FF 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 P22FF
What does P22FF mean?
P22FF means "SCR NOx Catalyst Inlet Temperature Too Low". Diesel engines raise exhaust temperature on purpose so the SCR catalyst can reduce NOx; this code reports that the gas entering the SCR stays too cold despite that. It is a generic code, so it means the same on every make.
Is it safe to drive with P22FF?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P22FF fail an emissions test?
Yes, it can. P22FF 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 P22FF to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P22FF clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.