Look at the phenomenon, check the circuit

For electronically controlled diesel engines, the following two conditions will also lead to diesel engine power shortage.Thermal protection: If the temperature of the electronically controlled diesel engine is abnormal, the temperature of the coolant may be too high;High intake temperature;Fuel temperature is too high;Coolant temperature sensor circuit fault (such as open circuit);Circuit fault of intake temperature sensor (such as open circuit);Fuel temperature sensor circuit fault (e.g. open circuit), etc.When the above phenomenon occurs, the ECU will automatically enter the thermal protection state.Thermal protection devices are commonly used in electronically controlled diesel engines. When the temperature value exceeds the preset value, ECU will control the injector to reduce the amount of fuel injection, thus reducing the output torque and power of the diesel engine.Failure protection mode: if the electronic components of the electronically controlled diesel engine fail, it may be the rail pressure sensor damage or line fault;Fuel metering valve drive failure, valve damage or line failure;The diagnostic instrument showed that the throttle could not reach full opening, etc.Plateau dressing results in;Rail pressure sensor signal drift;High pressure oil pump closed-loop control faults;Pressurized pressure sensor is damaged or line fault;The CAM signal loss is displayed by the diagnostic instrument (the influence on the starting time is not obvious when the CAM signal is operated only by the crankshaft signal), etc.The diagnostic instrument shows the signal loss of crankshaft (running only by CAM signal, the starting time is long), etc.The ECU will automatically enter fail-safe mode.A diesel engine can only operate at a certain speed.The purpose is to avoid the diesel engine to have more trouble and to the vehicle equipment to repair shop.