What is the reason why the fault light of Fit engine is on?

The reasons for the failure light of Fit engine are: 1, and the exhaust emission is not up to standard, such as poor fuel, failure of three-way catalyst, too much carbon deposit in intake pipe, blocked fuel nozzle, failure of oxygen sensor, and occasional engine misfire. The engine fault light will be on, and the engine fault light is usually on because of poor oil quality. 2. Turn on fault lights due to poor engine system: such as accelerator pedal sensor, throttle position sensor, air flow meter, crankshaft position sensor, etc. Otherwise, poor line contact will cause the engine fault light to light up. 3. Gearbox system failure of some vehicles: it is also indicated by engine failure light, such as internal failure of gearbox, slipping and high temperature.