P243B code meaning
Particulate Filter Restriction - Forced Limited Power (Bank 2)
Powertrain system Generic code P24xx codes Check engine light
What P243B means
P243B means the second particulate filter is so restricted that the engine controller cuts power to protect engine and filter. Ford documents the code in its 2024–2025 OBD summary for gasoline engines, as part of the gasoline particulate filter monitor next to P246C for bank 1. Once the filter has been above 250 °C for 30 s and exhaust flow lies between 400 and 850 m³/h, a normalised back pressure above 1.0 for 5 s sets the fault. That makes it one of the few bank 2 filter codes with public thresholds, and it shows the code is not limited to diesels. Likely causes are a filter overloaded with soot or ash, a dented pipe, or a pressure sensor or hose reading too high. Until the restriction is cleared the engine stays in reduced power. A high soot load on this bank without the power limit is P243F.
P243B at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P243B
- Noticeably reduced engine power
- MIL on
- Poor acceleration at higher speed
Common causes of P243B
- Most likelyBank 2 filter overloaded with soot or ash
- PossibleDamaged or blocked exhaust pipe on bank 2
- PossiblePressure sensor or hose on bank 2 reporting too high a pressure
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
DPF b2
What each part of P243B means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 3B | The exact fault in that area. |
What to do next
- Note P243B 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 P243B
What does P243B mean?
P243B means "Particulate Filter Restriction - Forced Limited Power (Bank 2)". P243B means the second particulate filter is so restricted that the engine controller cuts power to protect engine and filter. It is a generic code, so it means the same on every make.
Is it safe to drive with P243B?
Drive gently and only to a workshop. With P243B the car can go into limp mode (reduced power) to protect itself.
Will P243B fail an emissions test?
Yes, it can. P243B 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 P243B to fix?
Difficulty: hard. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will P243B clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.