Some failures will inevitably occur when the equipment is used for a long time. After investigation, it is found that there are three main types of failures: circuit failure, mechanical failure and external interference.
1. Circuit failure
When the power is turned on, the ABS indicator light should be on, and once the vehicle speed reaches 10km/h, the indicator light should automatically go out, otherwise it means that the ABS is malfunctioning.
ABS pressure regulators all use solenoid valves, which may burn out if the voltage is too high, and make it unable to work normally if the voltage is too low.
Generally, the power supply voltage should not exceed ±15% of the rated voltage of the solenoid valve. The same problem exists for the electronic control unit, otherwise the ABS will malfunction.
2. Mechanical failure
The impulse ring is an iron gear ring, which changes the magnetic field of the sensor. It is fixed on the hub and does not contact any parts. In this regard, some people don’t understand, mistakenly think that the pulse acts as the transmission of the gear, and add lubricating oil or lubricant to it, so that iron filings and other debris will accumulate on it, and the accumulation of impurities will inevitably destroy the sensitivity of the sensor.
The impulse ring has a different axis from the wheel hub, and the gap between the sensor and the impulse ring is variable, which will affect the test accuracy of the wheel movement. The reasons for this situation are roughly improper installation method of the impulse ring, deformation of the impulse ring (unnecessary impact on the impulse ring when the vehicle is under warranty), wear and loosening of wheel bearings, etc. The damage of the impulse ring will also affect the accuracy of testing the four-wheel motion state parameters.
In case of the above situation, when the impulse ring needs to be replaced, the problem of the sensor and impulse ring should be determined again (0.2~0.5mm).
3. External interference
The pressure regulator, ABS circuit is good, and the sensor can accurately measure the wheel movement state.
Poor ABS performance, such as increased braking distance, loss of control of anti-lock pump action, etc., is caused by a failure of the pressure regulator.
The minor fault of the pressure regulator is slow response and improper gain, and the serious fault is that the work is not controlled by the ABS, and the normal braking function cannot be restored when the ABS is disengaged.
The above are the fault categories and treatment methods of WABCO abs. In addition, the anti-lock brake system must be regularly maintained during use to reduce its failure rate.