• Categories:Industry news
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• Time of issue:2021-09-23 16:45
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(Summary description)The fan is only high speed or low speed 01 The fan motor can only operate at high speed or low speed. 02 Troubleshooting ① Check whether the double temperature switch is faulty. If it is damaged or works abnormally, replace it. ② The second gear relay of the fan is faulty. Replace the fan relay. ③ Fan motor failure, repair or replace. ④ Repair the control circuit of the fan for open circuit, short circuit or poor contact. The engine cooling fan does not stop Refer to the table for the fault phenomena and troubleshooting methods of the engine cooling fan without stopping. Table fault phenomena and troubleshooting methods Engine cooling fan does not turn 01 The engine coolant temperature is too high and boiling occurs, but the cooling fan does not turn. 02 Troubleshooting ① Check the dual temperature switch (or coolant temperature sensor). Unplug the double temperature switch plug and jumper the two terminals of the plug. When the fan works normally and the radiator coolant temperature reaches the normal working temperature of the fan, it indicates that the double temperature switch is faulty and should be replaced; Otherwise, it indicates that other parts of the cooling system are faulty and should be further overhauled. ② Check the fan motor. When 12V DC voltage is directly connected to the two terminals of the fan motor, the fan works normally, indicating that the fan motor is normal, and the fault of the fan control circuit shall be eliminated; Otherwise, it indicates that the fan motor is faulty and should be replaced. Unstable idle speed 01 The unstable idle speed shows that the engine trembles and the speed is uneven during idle operation. The causes include blockage of idle air measuring hole, poor operation of idle device, weak spark of spark plug of individual cylinder, loose sealing of individual valve, air leakage of intake manifold, premature or too late ignition time, improper idle adjustment, etc. 02 Troubleshooting When the idle speed of the engine is unstable, adjust the idle speed first. If the fault still cannot be eliminated after idle speed adjustment, check whether the idle speed measuring hole and idle air measuring hole are blocked. If the measuring hole is blocked, it can be cleaned with gasoline and blown through with compressed air. If the measuring hole is not blocked, stabilize the engine speed at a certain speed, and observe whether there is air leakage at the intake manifold and lower gasket. If there is air leakage, it can be eliminated by fastening screws or adding or subtracting gaskets. If the unstable idle speed is accompanied by the decrease of engine power, further check whether the working condition of spark plug, valve sealing performance and ignition time are correct, and repair and adjust it if necessary.