What Causes the Horn to Work But the Engine Not to Start?

[CollinMarie]

Reasons why the horn works but the engine does not start are as follows: Poor quality, substandard gasoline: Shortly after refueling, the engine warning light on the car's dashboard comes on; this is usually because poor-quality gasoline was added at an unregulated gas station, leading to incomplete combustion of the air-fuel mixture during engine operation, which triggers the engine warning light. Spark plug carbon buildup: Carbon buildup on spark plugs can cause poor engine performance, resulting in difficulties starting, unstable idling, poor acceleration, backfiring during rapid acceleration, excessive exhaust emissions, increased fuel consumption, and other abnormal phenomena. Oxygen sensor failure: The oxygen sensor is a fairly durable component. As long as the fuel quality is up to standard, it can last for 3 years or longer. Therefore, if the warning light comes on in a new car, it might be worth checking if the oxygen sensor plug is loose.