P0555
- Powertrain
- Generic (SAE)
- Safety
Stop driving
Continuing to drive risks injury or major mechanical damage. Shut the engine off when it is safe to do so.
Brake Booster Pressure Sensor Circuit
This code is in our catalogue but has not yet been through editorial review, so the guidance below is limited to what our structured data supports. We publish deeper diagnostic content only after a code has been reviewed — here is why.
A general circuit fault is detected on the brake booster pressure sensor - the ECU cannot determine vacuum reserve in the booster, which limits the safe operation of stop-start, regenerative-braking blending, and electric vacuum pump control.
A trouble code records what a control module measured. It does not identify which part failed. Test before replacing anything.
- Safe to drive
- Continuing to drive risks injury or major mechanical damage. Shut the engine off when it is safe to do so.
- Urgency
- Stop driving
- Will it pass emissions
- Not affected
- Check engine light
- Solid
- Significant power loss / limp mode
- Possible blue or black smoke from exhaust
- Whistling or hissing sound from intake
Many vehicles show no symptom at all beyond the warning light. The absence of a symptom does not mean the fault is not real.
| # | Cause | How often | Component |
|---|---|---|---|
| 1 | Open in sensor or wiring | Very common | — |
Ordering reflects how often each cause is responsible in general, not a probability for your vehicle. Confirm by testing.
- Brake Booster Pressure Sensor
- Definition
- Generic code set (SAE J2012 / ISO 15031-6) via the OBDexopen database, dedicated to the public domain under CC0-1.0.
- Diagnostic guidance
- Written and reviewed in-house. See our editorial policy.
- Review status
- Awaiting review
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