What Causes the Tachometer Not to Return to Zero?

[Jasper]

The reasons why the tachometer does not return to zero: 1. The speedometer in the vehicle's instrument cluster malfunctions, causing the tachometer needle to stop moving; 2. The vehicle's mileage sensor fails. Check if the flexible shaft connection is disconnected, then observe whether the mileage starts to increase. If only the tachometer stops working, a new one must be replaced; 3. Foreign objects inside the instrument panel are stuck and cannot move. Open the instrument panel to remove the foreign objects. The tachometer is usually located within the instrument panel, symmetrically placed alongside the speedometer. The tachometer operates based on magnetic principles, receiving pulse signals generated when the primary current in the ignition coil is interrupted, and converting this signal into a displayable speed value. The faster the engine speed, the more pulses the ignition coil generates, resulting in a higher displayed speed value on the gauge.