In four to five to six of the country's emergence, postprocessing of fault is also more and more, but most of the garage is heard do not know how postprocessing fault repair does not even take this live, do not want to earn the money, not only can not take repair.

Today, we have sorted out some of the processes related to post-processing, troubleshooting, and what essential tools will be used.

Understanding principle

Postprocessing maintenance is a system, compared with the Baotou beiben vehicle circuit card parts relatively simple, its working principle is in need when spraying urea, do not need not spray, as long as the postprocessing system can work well enough; for example, a set of SCR system needs DCU beam line, urea pump assembly Nox sensor, temperature sensor, exhaust nozzle, urea tank (liquid level sensor) with each other, at the same time injection conditions can work.

Vehicle maintenance diagnosis

For the diagnosis of operation, need to use the vehicle diagnostic apparatus, now the brand diagnostic instrument on the market is uneven, the quality is good or bad, as long as it can help to judge the fault direction, we will be able to meet the use, of course, the more powerful the more detailed the better, a price of a goods.

Most of the diagnostic instruments will post processing fault description, for example:

441:SCR urea pressure build-up error;

The actual average conversion efficiency of 432/ P0420:SCR is lower than the threshold value of 2, and the discharge exceeds 7;

453/ P2049:SCR urea nozzle drives high end short circuit for power supply.

Then we know how to analyze the fault, how to start maintenance.

Diagnosis of post processing parts

The maintenance of the parts after processing is relatively simple, mainly divided into mechanical part and circuit part.

The mechanical part is the external parts, such as urea nozzle clogging, only need to be removed, soaked in hot water, using steel needle through the nozzle.

Baotou beiben heavy truck parts is the circuit fault sensor fault and urea pump failure, Baotou beiben heavy truck parts sensor fault is relatively simple, we only need to use a multimeter to detect and judge the sensor is normal, if there is a problem can be solved.

If is the urea pump problem, so we need to use the postprocessing system diagnostic apparatus can simulate the urea pump on the vehicle working condition, and can automatically detect the internal parts of urea pump working state, in order to determine the replacement parts, this is the fastest way to repair, of course a lot of experience in the maintenance of the master, can to determine the fault location based on urea pump work sound, but just contact for postprocessing maintenance personnel, postprocessing system diagnosis instrument is essential equipment.

Disassembly and assembly of urea pump

Check complete failure, we need to change parts of urea pump, and now a lot of people after the failure of postprocessing directly for assembly, actually this kind of practice is very wrong, a lot of the time because it is not clear whether the maintenance principle, so the direct change to solve the problem, but the cost of thousands of dollars will let owners a headache. That may be because of this once lost an old customer maintenance.

The disassembly and assembly of the urea pump is also simple, and the parts which are often broken are also a few. It is clear that the principle and disassembly methods of these components can be done.

Loading test

The last thing to do is to test the loading, quality on vehicle exhaust back pressure and the need for detection, detection of back pressure is relatively easy, by measuring the vehicle exhaust back pressure back pressure tester, SCR muffler blockage judgment based on peak can back pressure value, if beyond the factory calibration standard value, usually resolve the method is to replace the assembly or postprocessing silencer for cleaning, this set of postprocessing maintenance end.

Let's sum up the process of post process maintenance and the tools and equipment involved:

The first step is to detect the fault after the diagnosis by the diagnostic instrument

Second step sensor detection, using multimeter to measure the sensor voltage

Third step urea pump detection, the use of post-processing system diagnostic instrument to detect urea pump

Fourth step urea pump disassembly, disassembly and assembly urea pump replacement original

Fifth step muffler overhaul, the use of back pressure gauge to detect the blockage of muffler

Sixth step loading test and trouble shooting