P050F code meaning
Brake Assist Vacuum Too Low
Powertrain system Generic code P05xx codes Check engine light
What P050F means
GM (from about model year 2017/18) monitors the brake booster with a vacuum sensor: with the pedal at rest and high intake vacuum the booster must hold its vacuum; a loss over time is filtered as a drift ratio, and above a threshold P050F sets, MIL after two trips. It runs with the engine on, during start-stop auto-stops and after switch-off. Without enough brake vacuum the module must throttle, restart the engine from auto-stop or request a pump – which affects idle and start-stop – and brake assistance can drop. Ford and FCA do not use P050F.
P050F at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of P050F
- Check engine light on
- Hard brake pedal, especially after auto-stop
- Hissing at the pedal, start-stop stops less often
Common causes of P050F
- Most likelyLeaking vacuum hose or check valve
- PossibleLeaking diaphragm in the brake booster
- PossibleVacuum sensor or its seal faulty
- Less likelyElectric or mechanical vacuum pump weak (where fitted)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Brake boosterBrake booster vacuum sensorVacuum hoseEngine control module
What each part of P050F means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 5 | Area: vehicle speed, idle control and auxiliary inputs. |
| 0F | The exact fault in that area. |
What to do next
- Note P050F 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 P050F
What does P050F mean?
P050F means "Brake Assist Vacuum Too Low". GM (from about model year 2017/18) monitors the brake booster with a vacuum sensor: with the pedal at rest and high intake vacuum the booster must hold its vacuum; a loss over time is filtered as a drift ratio, and above a threshold P050F sets, MIL after two trips. It is a generic code, so it means the same on every make.
Is it safe to drive with P050F?
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 P050F fail an emissions test?
Yes, it can. P050F 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 P050F to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P050F 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.