Anti-lock Braking System





Welcome to our Anti-Lock Braking System area. Here you will Find information on ABS and how we diagnose faults.

What is ABS?

Anti-lock Braking - Commonly known as 'ABS' is a saftey feature that prevents the wheels locking up and avoid skidding when emergency braking is needed. ABS will help the driver to maintain steering control and decreases the braking distance in most conditions. ABS is made up of 4 main components:

- Speed Sensors - These are located on each wheel. If the wheels attempt to lock up, the sensors send this information to the ECU/Controller. 

- Valves - The valve is located in the brake line of each brake controlled by the ABS.

- Controller/ECUThe controller/ECU is a unit in the vehicle that receives the information sent from each of the speed sensors. If the sensor picks up that a wheel loses traction the signal is then sent to the controller/ECU.

- Pump - The pump is needed when a valve reduces the pressure in a line. The pump will then get the pressure back up.

ABS warning lights, Why do they come on? well this is because the ECU checks the operating sytem at all times while you are driving through the ABS sensors. The sensors constantly calculate and report information to the ABS ECU afixed to the side of the ABS Hydraulic Unit.

If there is a problem then the light will come on, this is usually due to a sensor that has broken down or a faulty wire. To diagnose the fault the vehicle will need a Diagnostic Test to see what the fault code is. We have the Diagnostic equipment to programme any ABS unit if one has to be replaced and to erase any fault codes stored in the ECU from a faulty sensor after repairs have been carried out. 

If you would like to read some more information on diagnostic testing then please visit our Diagnostic area.

If your vehicles ABS Warning light is showing, please contact us to book your car in for a Diagnostic Test.

French diagnostic services ABS ECU.jpg ABS Pump.jpg ABS-Wheel-Sensor.jpg

At FDS we are able to carry out all repairs to any part of the ABS system on or off the vehicle including brake bleeding. We also carry out all repairs to the Brakes that are not associated with ABS such as supplying and fitting Brake discs, Brake pads and Brake calipers.

Some systems need the Diagnostic Machine to bleed the brakes so if in doubt please do not hesitate to contact us.



Click here to visit our FDS Parts Shop to see all the new & used parts for your Citroen, Peugeot or Renault


ABS ECU's - ABS Control Units - ABS Modulators - ABS Pumps/Modulators Combined - ABS Pumps - ABS Wheel Sensors - Brake Assist Units - Brake Calipers - CV Joints Inner - Driveshafts - Hub Assembiles - Speed Sensors.