P25BD code meaning
Unmetered Fuel - Forced Engine Shutdown
Powertrain system Generic code P25xx codes Check engine light
What P25BD means
P25BD protects against engine runaway, where the engine keeps speeding up although the controller injects no fuel, for instance because oil from a failed turbocharger seal or combustible vapour drawn into the intake is being burned. GM documents the monitor in its diesel ECM tables. In 14OBDG04 the speed must pass 5,400 rpm for 0.01 s, after which the controller cuts the air supply with its intake air valve and disables the injectors; 18OBDG04 uses 5,500 rpm for 0.5 s and 20OBDG04 5,200 rpm for 0.1 s, both enabled above 1,500 rpm. Each table rates it Type A, so the MIL comes on in the first trip. Unlike P0219, which merely records an overspeed, P25BD means the engine was forcibly stopped. Before a restart, turbo, crankcase ventilation and intake tract should be checked for oil.
P25BD at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor2 to 20 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P25BD
- Engine revs up uncontrollably and then shuts off
- Heavy smoke from the exhaust before shutdown
- Check engine lamp on immediately
- Possible severe engine damage after the event
Common causes of P25BD
- Most likelyTurbocharger seal failure feeding oil into the intake
- PossibleOil carry-over from crankcase ventilation, e.g. overfilled or diluted oil
- Less likelyCombustible vapour drawn in from the surroundings
- Less likelyErroneous engine speed signal or controller fault
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Turbocharger sealsIntercoolerIntake manifoldAir shutoff valve
What each part of P25BD means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 5 | Area: vehicle speed, idle control and auxiliary inputs. |
| BD | The exact fault in that area. |
What to do next
- Note P25BD 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 P25BD
What does P25BD mean?
P25BD means "Unmetered Fuel - Forced Engine Shutdown". P25BD protects against engine runaway, where the engine keeps speeding up although the controller injects no fuel, for instance because oil from a failed turbocharger seal or combustible vapour drawn into the intake is being burned. It is a generic code, so it means the same on every make.
Is it safe to drive with P25BD?
Drive gently and only to a workshop. With P25BD the car can go into limp mode (reduced power) to protect itself.
Will P25BD fail an emissions test?
Yes, it can. P25BD 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 P25BD to fix?
Difficulty: workshop only. A typical repair takes 2 to 20 hours of work. This is a job for a workshop.
Will P25BD clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.