Code P0501: Speed ​​Sensor Signal (Vehicle)

This error causes the speedometer to stop registering or the car to jerk when downshifting.

• What the car is saying: “I don’t know how fast the car is going.”
• Common Cause: In modern Citroëns, the speed measurement doesn’t come from a sensor in the gearbox, but rather from… ABS wheel sensors. If a wheel sensor fails or is dirty, the speed signal disappears.
• Solution: Cleaning the ABS wheel sensors or replacing the faulty sensor (usually the rear left one on some models).