{"answer_summary":{"analysis":"","answer_id":"18863249","attention":"","car_part":"","category_id":0,"created_at":1659755081,"extra":{"additional_car_part":"","car_part_ids":[],"fault_conditions":[],"fault_desc":"","kilometers":"null","step":[{"text":"故障代码： P0420\n适用范围： 所有汽车制造商\n中文定义： 催化转换器系统效能低于阈值(第1排)\n英文定义： Catalyst System Efficiency Below Threshold (Bank 1)\n所属系统： 排放控制\n错误背景： Catalyst System Efficiency Below Threshold 催化转换器(也称作催化净化转换器)，是一个利用催化剂的作用将排气中的CO、HC和NOx转换为对人体无害的气体的排气净化装置。它一般位于排气管的消声器之前。电子控制单元(ECU)检测到氧传感器1/2的交换率跟1/1的交换率相当，因此推断催化转换器系统效率太低。故障原因包括排气管或排气歧管附近尾气泄漏，催化箱失效，发动机冷却液温度(ECT)传感器故障，发动机失火或正时滞后，机油太脏，氧传感器故障，燃油系统压力太高等。\n出现这种问题 那么主要就是考虑你的三元催化 那么更换了三种催化之后一个就是三元催化本身的质量问题 。\n第二个就是混合气问题 如果混合器出现混合气过浓 那么这种情况已会被导致转化效率过低的情况 。\n第三种情况就排气管存在漏气 就是前氧传感器以前的位置漏气漏气的情况 虽然催化后氧传感器检测的排气量变小 那么就会出现这种故障 \n第四种问题就是后氧传感器失效 这种情况只能更换后氧传感器"}]},"extra_friendly":{"car_parts":[],"comparing_series_list":[],"fault_conditions":[],"kilometers":"未知"},"id":"1661603","images":[],"mechanic_uid":"7769664","question_content":"","question_id":"2200681918","series_id":2033,"suggestion":"","updated_at":1659755081,"version":1},"car_info":{"brand":{"expert_mechanic_count":0,"id":95,"is_hot":0,"jinpai_mechanic_count":0,"letter":"F","listorder":52,"logo":"http://img.baichebao.com/brands_api/95.png","mechanic_count":414,"name":"福田","pid":0,"status":1},"series":{"brand_id":437,"cname":"风景G7","cover":"http://img.qcds.com/car-series/covers/2033.png","cover_big":"http://img.qcds.com/car-series/covers/2033.png","cover_small":"http://img.qcds.com/car-series/covers/2033.png","id":2033,"listorder":13,"name":"","pic":"","status":1}},"msg_action":"https://m.qcds.com/question/report/JURDJUE5JTlETSUxOSVDMyU3QiVDMk1qJUVGJTNGJUYxYiUxOCUyQQ==/JUJEJTNBJTAwJTNGJTIycSUwM18=?app=1","msg_content":[{"color":"#444444","text":"专家对您本次咨询做了总结，同时还给您描述了注意事项"}],"msg_icon":"http://img.qcds.com/upload/eb4ce0d7aa8752676eba08b5000040f3.png","msg_title":"问诊小结"}
