14 what is the reason why the forester's fault light is all on?

My forester was bought in Beijing in June1/kloc-0. When driving 1000 km, it was found that the engine fault light, anti-skid light and constant speed light were all on, and there was no cruise function. After clearing the fault code in Handan 4S shop, everything was normal. The 4S shop said that the throttle was dirty and the oil was not good, and then it happened seven or eight times. This problem happened again when I went to Shijiazhuang during the Spring Festival. The technicians in Shijiazhuang 4S shop determined that the fault code was that the mixture was too lean, and the air-fuel ratio sensor of the three-way catalyst had a problem, so it needed to be replaced from the fixed sensor in Japan. I went back to Handan 4S store to communicate, confirmed the cause of the failure, and agreed to set the sensor, because it can be replaced free of charge during the warranty period. Now the mileage is 35,000, and the above experience will be told to all riders. I hope you can give me more advice.