P0135 fault code refers to the fault of the first sensor in the first group of the heating circuit of the oxygen sensor. There are two rows of oxygen sensors. In OBD fault codes, you often see the expression of which row and which oxygen sensor, that is, the first row refers to the position of the first cylinder, that is, the first row, and the other row is the second row. No matter where the oxygen sensor is, the first sensor always refers to the upstream oxygen sensor, The second sensor always refers to the downstream oxygen sensor, the first
View full text>