去年 CEL 亮过几次, 经查码是
2C7F Oxygen sensor after catalytic converter, bank 2: Trim control ; frequency: 49
同时发现 down stream oxygen sensor 后面的排气连接螺栓锈坏,排气管漏气,因为开得少,准备夏天先折腾排气管连接,不行再换 O2 sensor.
如图垫片7处漏气