1Vehicle weakness, normal urea consumption
Trouble phenomenon: The vehicle owner responded that the vehicle was weak and the urea consumption was normal, and the muffler could be found to emit a small amount of white smoke after refueling.
Fault analysis: read the fault code with the diagnostic instrument to indicate that the engine emissions exceed the standard, and there is no other fault. The urea nozzle was removed and the diagnostic instrument was used for the injection test, and no abnormality was found. During the inspection, a large number of urea crystals in the high-temperature catalyst tube were found to be seriously blocked, so the exhaust elbow was removed and the gas belt was used to clean the soot attached to the ceramic surface of the catalyst. The failure of the test run after replacing the urea solution disappeared.
Fault summary: After the urea crystallization fails, a large amount of urea accumulates in the exhaust pipe, which not only causes the engine exhaust to be blocked and weak, but also causes the emission to exceed the standard, and the OBD is limited to torque after a few driving cycles. The main reason is mostly that the quality of urea is not up to standard.