Capteur de niveau d'huile défectueux

The sensor reporting engine oil level, faulty so the reading is unreliable. On engines with no dipstick it is the only measurement available, which raises the stakes considerably — a driver with no way to check independently has to believe it.

The asymmetry is what matters. Reading high on a low sump means no warning while the engine runs short of oil, which is the failure that destroys engines. Reading low on a correct sump causes needless topping up, and an overfilled engine aerates its oil and can damage the catalytic converter through the breather — so acting on a wrong low reading is itself harmful.

Many of these are combined level and temperature units in the sump, and they read by ultrasound or capacitance, so sludge or a coating on the sensor produces a plausible wrong value. Verify against a known quantity: drain and refill with the specified amount and see whether the reading agrees. A reading that never changes across an oil change is the clearest evidence of a failed sensor rather than a genuine level problem.