Why does the fuel light come on when there's half a tank of gas?

[McCaleb]

The reasons why the fuel light comes on when there's half a tank of gas: 1. Damaged fuel tank float sensor: First, use a multimeter to check the fuel pump and fuel level display to see if the float is damaged. 2. Car instrument display malfunction: Check the car's instrument panel; it might be a fault in the car's computer display. A professional technician should be consulted for troubleshooting. Fuel usage tips: Under normal driving conditions, when the fuel light comes on, the car can typically continue to drive for about 30 kilometers, depending on the driver's habits. Do not wait until the fuel light comes on to refuel, as the fuel pump is cooled by being submerged in gasoline. When the tank is empty, the fuel pump does not get sufficient cooling and can be easily damaged.

[MacGabriela]

I encountered the same situation during a long-distance trip before. There was still half a tank of fuel, but the fuel light suddenly came on, which really made me panic at the time. Later, after a check at the repair shop, I found out it might have been the fuel level float stuck in the tank—that thing measures the fuel level, and if it gets stuck in a low position, it sends false alarms. It could also be an issue with the fuel pump assembly, where a sensor inside isn’t working properly. Poor wiring connections can cause trouble too, like corroded connectors or broken wires, leading to inaccurate signals. Additionally, the dashboard itself might malfunction and display errors. This issue needs to be addressed as soon as possible; otherwise, an inaccurate fuel gauge can easily leave you stranded. I later spent 200 yuan to replace the float, and that fixed the problem. My advice is to get it checked at a professional repair shop early and not delay it.

[JohnMarie]

I've been driving for over a decade and encountered the half-tank warning light issue several times. This is usually caused by a faulty fuel level sensor – either stuck due to oil contamination or completely broken, leading to incorrect fuel level display. Wiring issues should also be checked, as short circuits, breaks, or poor connections in the wiring from the fuel tank to the dashboard can cause signal transmission errors. Additionally, fuel tank deformation or bent float rods in the fuel pump assembly can create problems. A friend's car had this issue last time – the fuel tank bottom was dented and deformed, restricting float movement. Dashboard instrument failures are relatively rare but should also be considered. It's best not to DIY – take it to a repair shop to read fault codes with diagnostic equipment to identify the specific cause before repairing. Safety first.

[Dave]

A while ago, my car's fuel light came on, but when I checked, there was still half a tank of fuel left. My first thought was that the dashboard was faulty. After consulting a mechanic, I learned that more often than not, it's an issue with the fuel level float. It floats on the fuel surface to measure the height and can get stuck by debris, causing false alarms. The sensor in the fuel pump module might also malfunction, sending a low fuel signal even when there's plenty left. Loose or aged wiring connections can also cause problems. I tried tapping the fuel tank a few times, which temporarily fixed it, but the issue returned after a few days. The mechanic said this was only a temporary solution, and in the end, replacing the entire fuel pump assembly was the permanent fix. It's recommended to focus on checking the sensors and fuel pump during inspections.