What are the faults caused by rusting of automotive wheel bearings?

Today, I will talk to you about the car wheel bearings. If there is rust, it may cause these malfunctions.

[Case] Dongfeng Nissan Tianzhu sedan driving impact. Fault phenomenon: The 2012 Dongfeng Nissan Tianzhu 2.3L sedan is equipped with a continuously variable transmission (CVT) with a mileage of 120,000 km. When the car travels to 30km/h, the transmission suddenly hits, and then with the increase of the speed, the engine speed remains unchanged at 3000r/min. When the vehicle speed reaches 100km/h, the engine speed drops to 2500/min.

Fault diagnosis and analysis: Connect the fault diagnosis instrument and read the fault codes of the engine and transmission to show that there is no fault code in the engine and transmission system. The data flow of the engine was read and no abnormality was found. Reading the data flow of the transmission, it is found that the main pressure is 0 at idle, and the valve body of the CVT is analyzed to be faulty. After replacing the valve body, when the car travels to 30km/h, the engine speed is maintained at 2400~2500r/min with the increase of the speed, but the transmission is still suddenly shocked at 30km/h.

At this time, the data flow of the transmission was read and it was found that the main pressure was 1.25 MPa. There are still faults in the analysis, but the engine and the transmission have no fault codes, and there is no problem from the data flow. At this moment, I suddenly thought that ABS had a fault code, that is, U1000: communication system failure, because ABS and CVT were irrelevant, and I didn't care at the time. I thought of this problem when the fault diagnosis was deadlocked.

Fault code U1000: Communication system failure, where should I start diagnosis? According to the diagnosis process of the maintenance manual, no problem is found. Then I think of the ABS sensor of the four wheels, so I remove the wheel speed sensor of the right rear wheel and find the wheel bearing. If there is rust, spray it with a cleaning agent a few times, wipe it with a cloth, and then test the car. Road test, ABS warning light is on.

The impact of the transmission is gone. Read the ABS fault code and display the wheel speed sensor fault on the right rear wheel. The right rear wheel was removed and it was found that the original rust on the bearing surface was not cleaned. Troubleshooting: After re-cleaning, test the car and all the faults are gone.