What causes the ignition warning light to come on and then disappear after starting?
2 Answers
It is normal for the ignition warning light to come on and then disappear after starting. The warning light coming on after ignition is part of the self-check procedure, and the light turning off indicates that the car is functioning properly. Below are some faults related to the ignition warning light staying on: 1. Ignition system failure: A faulty ignition system can lead to poor engine combustion, requiring inspection and repair of the ignition system. 2. Carbon buildup: Excessive carbon buildup on spark plugs, irregular sparking, or no sparking can cause this issue, necessitating cleaning or replacement. 3. High-voltage coil pack: The high-voltage coil pack or high-voltage coil may be faulty, requiring checks on voltage and resistance to ensure they are normal. 4. Component failure: Faulty related components can result in poor combustion in the engine cylinders, triggering the ignition warning light.
I've encountered a similar situation where the ignition warning light comes on and then disappears during startup, which is usually a normal response of the car's self-check. The moment the vehicle is powered on, the computer quickly scans various components of the engine system. The warning light turning on indicates that the system is being checked, and if no issues are found, it will automatically turn off. However, if this light frequently flashes or is accompanied by difficulty starting, you should be cautious. Possible reasons include unstable battery voltage, especially in cold weather; or a sensor reacting a bit slow, such as the crankshaft position sensor having unstable signals during startup. It's recommended to observe whether this always occurs under specific conditions, such as during humid weather or cold starts. If it happens occasionally, there's no need to worry, but if it persists, you should check if the battery connections are loose or if the sensors need cleaning.
