C0551
Longitudinal Acceleration Sensor Circuit/Open
Open circuit on the longitudinal acceleration sensor (used by ESP/ESC for braking-direction stability).
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
Common causes
Ordered by how often each turns out to be the cause.
- Wiring openCommon
- Pin pushed back out of connector bodyLess likely
- Cracked solder joint inside the module or sensorLess likely
Parts involved
- Longitudinal Accel Sensor
- Sensor Wiring
C0551 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.