Generic fault code
P0559 — Brake booster pressure sensor, circuit: intermittent
The control unit stores code P0559 when it detects this fault: “Brake booster pressure sensor, circuit: intermittent”.
Indicative severity: HighFuel and air metering
Reviewed by Daniel Morales, founder of Reprorace SL, on
What does code P0559 mean?
The engine measures the incoming air and meters the fuel so the mixture is right; the throttle, the accelerator pedal and the turbo are here too. A fault usually shows as higher fuel use, jerking, lack of power or hard starting.
- System
- P · Powertrain
- Area
- Fuel and air metering · Car system: Turbo
- Type
- Generic (SAE J2012 / ISO 15031-6): the same meaning on every make
- Indicative severity
- High. Diagnose as soon as possible: it may affect safety or cause damage (engine, catalyst, brakes).
What usually causes code P0559?
- Loose or corroded connector, backed-out terminals
- Damaged, chafed or pinched wiring
The most likely causes come first. Only a check on the car confirms which one is yours.
What are the symptoms of code P0559?
- Lack of power, especially as revs rise
- Limp-home mode: the engine limits its power
- Whistling, hissing or black smoke
These are the usual symptoms of this kind of fault: not all of them always appear, and sometimes you notice nothing.
Can I keep driving with code P0559?
Better not, except when you really have to. This fault may affect safety or damage the engine, the catalytic converter or the brakes. See a workshop as soon as possible; if you must move the car, drive gently and only short distances. If the light flashes, the car loses power, makes unusual noises or the brakes or steering feel different, stop somewhere safe and call for assistance.
This is guidance only: only someone who checks the car can say whether it is safe to drive.
An indicative description of the code's generic meaning. Each manufacturer may give it a different meaning, conditions or tests: always follow its service information and your workshop's advice.
What you can do yourself
For this kind of fault
With the engine cold, check that the turbo and intercooler hoses are not loose, split or oily. Until it is fixed, avoid heavy loads and steep climbs.
Read the code and keep the report: with an ECO-LITE in the OBD socket you see it on your phone or computer, with the data captured when the fault happened.
Look for anything obvious: a loose connector, a disconnected hose, a fuel cap not closed properly or a low fluid level. Do not take apart anything you do not know.
Clear the code only after writing it down or after the repair. Clearing turns the light off, but it also deletes the freeze-frame data and the readiness monitors used at the inspection.
Drive normally for a few days and read the codes again. If the code comes back, the fault is still there: book the workshop and bring the report.
Read your car's fault codes on your phone
With an ECO-LITE in the OBD socket you see the codes in your account, with the data captured when the fault happened, and your workshop can check them remotely, always with your permission.
Related codes
- P02CATurbocharger/supercharger B: overboost
- P02CBTurbocharger/supercharger B: underboost
- P0555Brake booster pressure sensor, circuit: malfunction
- P0556Brake booster pressure sensor, circuit: range/performance
- P0557Brake booster pressure sensor, circuit: signal low
- P0558Brake booster pressure sensor, circuit: signal high
P05xx codes: vehicle speed, idle control and auxiliary inputs
In the glossary
Read more: Remote OBD diagnostics: what it is, how it works and what it can't do