Inspection and analysis: maintenance personnel start the vehicle after receiving the vehicle, and the starter works but the engine cannot keep idling. There are multiple fault codes in the system when using the diagnostic instrument (Figure 1).
According to relevant circuit diagrams, bus terminals ki. 15n < 0 1, ki. 15n < 02 and ki. 15n.
Replace F02 fuse, and the fault will still appear. Check the F02 fuse and find that it is blown again. Re-analyzing the fault code, the fault code "129002- front oxygen sensor of exhaust gas catalytic converter, signal line: short circuit to ground" appeared, and the connectors of two front oxygen sensors were disconnected, and it was found that the F02 fuse was no longer blown. Check the two front oxygen sensor lines, and it is found that the fixing clip of 1 exhaust front oxygen sensor wire harness has fallen off, and the insulation layer of the wire harness has been worn (Figure 2). From the analysis of the above process, the fault was caused by grounding after the insulation layer of 1 train front oxygen sensor harness was worn out.
Troubleshooting: Handling 1 The harness of the oxygen sensor in front of the train is damaged, and the F02 fuse is no longer blown. Troubleshooting.
Summary: Fuses are blown, which is usually caused by short circuit or excessive circuit load. At this time, we should first consider whether the faulty vehicle is equipped with or modified with electrical equipment, and then consider the short circuit fault, and combine the fault codes related to short circuit to find the fault point quickly.