(1) Power circuit failure
　　The cause of the failure is that the regulator is dirty、Damp，Cause the charging voltage to be too high；Power polarity is reversed；Turn on the starter while charging；The engine is running，The battery connector is loose, causing the generator to directly supply power to the ECU；Oil stains during work、water、Dust causes leakage of power line connections, grounding, etc.。

　　 (2) Input/output circuit failure
　　The common fault is the burning out of the amplifying circuit components，Sometimes it is also accompanied by the burning of the steel line on the circuit board, etc.。This type of fault is very easy to occur when construction machinery is working for a long time with heavy load.、Poor engine cooling、Surface paint and welding repair work、Conditions such as overcurrent and overvoltage in the circuit。

The mechanism has two aspects：

One is that the temperature is too high, which causes damage to the material and insulation of the parts.；

The second is the ablation of components caused by overcurrent and overvoltage。So the working temperature of ECU cannot exceed 85℃，Pay attention to heat dissipation and cooling when working at higher temperatures,The engine can only be started after the temperature is normal，And do not cut off any connection lines of the ECU during operation。

　　 (3) Memory failure
　　 There are 4 commonly used memories，For erasable programmable memory (EPROM or EEPROM) failure，Can be processed by copying。A few ECUs are encrypted，The chip cannot be copied。

　　 (4) Special fault
　　For construction vehicles，Due to the special working environment，water、rain、snow、mud、dust、Erosion by oil, etc.、Long working hours under heavy load and severe shock and vibration during work，Will cause ECU deformation、Cracking、Component pin open circuit、Short circuit、Failures such as adhesion or component damage。

 

TCU transmission controller，Failure phenomenon

　　 1. Oil leakage Oil leaks from the gearbox housing or oil pan，One reason is due to aging of the seal，Caused by poor sealing；Another reason is that the poor manufacturing process causes trachoma in the shell。

　　 2. When the gear is switched on, the engine is turned off, and D or R is connected，The failure of the engine stalling may be caused by damage to the lock-up solenoid valve or the lock-up control valve.。

　　3. Gear lock, gearbox input、The output signal is incorrect or caused by the components themselves or poor wiring，Sometimes there are communication problems between the gearbox computer and other system computers.。

　　4. There is no response when entering the file, and the D or R file is hanging，Then after releasing the brake，The vehicle does not move。This situation is mostly due to damage to the input shaft or reverse clutch，Or the D/R brake is damaged。

　　 5. Hang D/R file impact，Impact of vehicle shifting during driving、Rush，It is also a common failure phenomenon of automatic transmissions，This may be due to dirty gearbox oil，Cause the valve body to jam。