What does it mean when a smart car suddenly won't start and shows three bars?

[StSkylar]

This indicates a transmission issue where the gear cannot be engaged. As an emergency solution, you can try repeatedly moving the gear shift lever back and forth. The transmission is a gearbox that alters the gear ratio and direction of motion. It is located between the clutch and the central drive. Its main functions are: changing the vehicle's driving force and speed (gear shifting) while keeping the engine's speed and torque constant; enabling the vehicle to move in reverse (direction change); and allowing the engine to remain running while the vehicle is stationary (neutral gear). Based on transmission types, gear transmissions can be categorized into three types: dual-shaft, three-shaft, and combined. The dual-shaft type has two main shafts (excluding the reverse gear shaft) and only requires one pair of gears for speed reduction. The three-shaft type has three main shafts (input shaft, intermediate shaft, and output shaft) and requires two pairs of gears for speed reduction. The combined type consists of two transmissions connected in series or parallel to achieve more gear positions with fewer gears.