故障现象一辆2010年出厂的长安铃木天语自动挡轿车(采用A4F 1.8 L发动机),累计行驶约为5.4万km,出现发动机起动着机后,怠速不稳,发动机故障灯常亮的现象。故障诊断接车后首先确认故障。发现发动机起动着机后,仪表盘上的发动机故障灯常亮,怠速运转一会后开始出现抖动。说明上述客户反映的故障现象确实存在。接着连接SDT检测仪,进入发动机系统读取故障代码为P0171,含义是燃油系统混合气 Fault phenomenon A 2010 Changan Suzuki Tianyu automatic sedan (with A4F 1.8 L engine), the cumulative total of about 54,000 km, there engine start the machine, the idle speed instability, the engine fault light is always lit. Troubleshooting After the car first confirmed the fault. After the engine was found to start the engine, the engine fault light on the dashboard was always on and jitter began to appear after idling for a while. This shows that the above customer fault phenomenon does exist. Then connect the SDT detector, enter the engine system to read the fault code P0171, meaning the fuel system mixture