What causes the service light to indicate an engine fault?

[LilahFitz]

The following are specific reasons and solutions for the engine fault light being on: 1. Carbon buildup in the car causing ignition difficulties: Accompanied by slight shaking at idle, simply clean the throttle body and fuel injectors. 2. Weak spark plug ignition energy: Spark plugs not replaced after the maintenance cycle, leading to severely reduced ignition energy and misfires. 3. Insufficient fuel system low pressure: Low fuel pressure directly causes the engine to ignite twice, specifically check the fuel pressure regulator, fuel pump, fuel filter, and internal lines. 4. Battery depletion: Jump-start the car or use another battery. 5. Incorrect engine timing: Engine timing not matching the engine, replacing the alternator belt on certain engine models may cause the timing to skip, resulting in ignition difficulties.