U0418: Ungültige Daten vom Steuergerät A der Bremsanlage empfangen
Was zu tun ist
Your brakes still work — but the pedal may feel different, and that is the thing to be ready for.
On a car like yours some of the braking normally comes from the electric motor recovering energy, blended invisibly with the ordinary brakes. When that blending cannot be trusted, the car falls back to the friction brakes alone. Expect a pedal that feels harder or longer than usual, needing more effort for the same slowing — and expect the car to coast much further when you lift off, because the motor is no longer slowing you.
Leave a lot more room than usual until you have got used to it, and take particular care in traffic where you are used to one-pedal driving.
Get it looked at promptly rather than living with it. A brake pedal that has changed feel needs testing properly — a data fault and a genuinely failing electric brake booster produce similar symptoms and are very different problems, and only a proper check tells them apart.
Was dieser Code bedeutet
The brake system control module is broadcasting data that cannot be accepted as true. See U0400 for the family's framing and U0415 for the anti-lock module, which is a related but distinct unit.
Where a vehicle has a brake system control module separate from the anti-lock module, it is usually because braking has become partly electronic in a deeper way — an electric brake booster, a brake-by-wire arrangement, or the blended braking used on hybrids and electric vehicles.
Blended braking is the case worth explaining, because it is now extremely common and its failure has a distinctive feel. On a vehicle that recovers energy when slowing, pressing the brake pedal does not directly and only apply the friction brakes. The module decides how much retardation comes from the motor acting as a generator and how much from the pads, blending them so the driver feels one continuous response. The values it publishes — how much braking is being delivered, and by which means — are what the powertrain needs in order to do its half.
When those become implausible, the system falls back to friction braking alone, and that produces a specific, reportable symptom: a brake pedal that feels different — usually longer, harder, or requiring noticeably more effort for the same deceleration — and a car that no longer slows when the driver lifts off.
The critical reassurance, and it should be stated plainly: the friction brakes remain. A fallback to conventional braking is a designed-in behaviour, not a loss of braking. But the pedal feels different at exactly the moment the driver is not expecting it to, and that is worth being ready for rather than discovering in traffic.
So the advice is: expect a firmer or longer pedal, expect the car to coast further when you lift off, leave more room, and get it seen promptly — an electric booster that has genuinely failed is a different and more serious matter than a data fault, and only testing distinguishes them.
Wahrscheinliche Ursachen
Hier anfangen
- Drucksensor des Bremskraftverstärkers defekt · mittel
- Korrodierter oder loser Stecker · einfach
- Datenbusleitungen beschädigt · mittel
Seltener
- Steuergerät des Bremssystems defekt · Fachwerkstatt
- Eingang des empfangenden Steuergeräts defekt · Fachwerkstatt
- Raddrehzahlsensor defekt · mittel
Symptome
Beteiligte Bauteile
Information, keine Handlungsanweisung
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