C0551Longitudinal Acceleration Sensor Circuit/Open
- Generic OBD-II code · Chassis
- Can trigger limp mode
- How the car detects it
- C0551 reports an electrical break in the longitudinal acceleration sensor circuit: the brake or stability module no longer gets a usable fore-aft signal, usually because the signal or supply wire is open or a plug has lost contact. Earlier layouts mounted a separate g-sensor close to the centre of gravity and cabled it to the ABS unit; a Kelsey-Hayes patent (now ZF) describes a capacitive element whose analog voltage rises with acceleration and moves it onto the ABS circuit board to drop wiring and connectors. No manufacturer explains C0551 in a public document. Without the input, four-wheel-drive ABS loses its wheel-independent speed reference and stability functions are normally switched off with ABS/ESC lamps lit, while base braking remains. C0553 and C0554 cover a low or high voltage, C0552 an implausible value.
- What you may notice
- ABS and/or ESC warning lamp on
- Stability, traction or hill-start assistance unavailable
- ABS on four-wheel-drive vehicles regulates less precisely
- Likely causes
- LikelyBroken signal or supply wire between sensor and brake module
- PossibleCorroded, loose or pushed-back terminal at the sensor plug
- RareInternal open in the sensor or, on integrated designs, in the ABS/ESC unit
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.