KS Motorcycles K-LIGHT125, Maintenance Manual

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areas repair electronically controlled gasoline injection engine. This manual first introduces the
composition and working principles of electronically controlled gasoline injection system. Next, the
structure and performance of various components of the system are described in detail.
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In general, fault diagnosis instrument is an essential tool in the maintenance of electronically controlled
gasoline injection system. The fault diagnosis instrument can be used to call the fault information record
stored in the ECU out. To help the reader understand the true meaning of each fault code, this manual
lists the conditions under which the ECU sets various fault information records. However, many faults
are not directly determined based on the fault information record, but a series of analyses are required to
find the true fault. Therefore, this manual uses quite a bit of space to describe how to find the true fault
based on the fault information record.
Due to the presence of electronic control components, new contents are given to the cause of engine failure.
In other words, the same engine fault may be caused either by mechanical components or by electronic
components. Moreover, the actual fault of engine can be diagnosed not just with the fault diagnosis instrument.
Therefore, this manual also starts from the symptoms of the engine, and finds the fault in combination with
electronic control system.
18.2 EFI Parts
18.2.1 Engine Controller (YESON ECU)
The engine controller is used to detect the running state of engine in real time through various sensors, and
ensure the original motorcycle emission and fuel economy while optimizing the driving performance of
motorcycle under various working conditions through reasonable calculation and self-learning control output
devices. The engine controller can also wake up the self-diagnosis when the system is faulty.
18.2.1.1 ECU Appearance
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