The reason why the ABS light is always on

The reason why the ABS light is always on

1. The battery voltage is too low or the fuse is blown;

2. The wire of the ABS system is disconnected, the plug is loose or the relay is not firmly connected;

3. The wheel speed sensor is bad;

4. The hydraulic adjustment device is not good;

5. The electronic control device is defective.

The hydraulic adjustment device and electronic control device are the core components of the ABS system. Such components are generally relatively precise and will not be easily damaged. As a car that has only traveled 10,000 kilometers, there is generally no breakdown. It is still necessary to start with routine inspections.

1. First check whether the battery voltage is 12V; .

2. Check whether the ABS fuse is normal;

3. Check the wires of the ABS system to see if there is any disconnection;

4. Check whether the plug connectors are firmly connected;

5. Check whether the relay is fixed firmly:

6. Check whether the wheel speed sensor is normal.

Remove the vehicle speed sensors of the four wheels and check whether the sensor head has any dirt. If there is dirt, wipe the dirt on the sensor head and reinstall it, and check whether the ABS warning light is normal.

The wheel speed sensor is composed of an electromagnetic induction sensor head and a magnetic ring gear, which is mounted on the hub and rotates with the wheel. When the tooth ring rotates, the tooth crest and the backlash alternately face the sensor head. When the tooth tip is opposite to the sensor head, the gap between the two is the smallest, and the magnetic field around the sensing line of the sensor is the strongest;

When the tooth gap is opposite to the sensor, the gap between the two is the largest, and the magnetic field around the induction line is the weakest. The alternating change of the magnetic flux produces an alternating voltage in the induction coil, and the frequency of this voltage changes in direct proportion to the speed of the vehicle. The vehicle speed sensor can transmit the vehicle speed signal to the electronic control device in time to control the braking force of each wheel.

If the electromagnetic induction sensor head attracts iron filings, the gap between the sensor head and the ring gear will change, so that the magnetic flux change is not obvious, the alternating voltage generated by the induction coil will be irregular, and the electronic control device will not be able to. Effectively control the braking force of each vehicle, so that the ABS light is always on.

On a vehicle with an ABS system, the head of the wheel speed sensor is easy to absorb dirt such as iron filings. When the ABS light is on, the system should be checked first.