After the throttle valve of Guowu freight car was changed, the muffler became hot.

1. It may be that the DPE particle trap is blocked, causing the alarm light to light up. The solution is to let the vehicle run at high speed and let the particles in the particle trap burn at high temperature, so that the exhaust system can be restored to normal and the exhaust can be smoother, and the problem of high temperature alarm can be solved.

2. It may be that the concentration of combustible mixture is too high, resulting in high exhaust temperature, so it is necessary to check the oxygen sensor or three-way catalyst. When the oxygen sensor fails, the fuel injection quantity will be out of control, resulting in high mixture concentration.

3. The exhaust temperature is high, and it is also possible that the fuel pump or ignition coil is faulty, so it is necessary to replace the fuel pump and ignition coil in time, otherwise the vehicle will shake and accelerate.

4. If the cylinder pressure is too high and the ignition time is inaccurate, it will also lead to an alarm of high exhaust temperature. This kind of fault is beyond the owner's control. It is best to read the data stream with faulty equipment in the repair shop, and then adjust the ignition time and fuel injection quantity.