Vehicle Anti-Lock Brake System (ABS) Diagnostics

Vehicle computerised diagnostics Mobile service for vehicle ABS repair   in Shropshire & Mid Wales - Shrewsbury and  surrounding areas.

Telephone 07703 558610 for booking.

ABS Sensors Supplied

ABS Warning light on ?
Private Customers, Fleet  & Motor trade Welcome.
Unsure if you should drive the vehicle with an ABS warning light on ?
Our mobile autoelectrical service comes to you.

ABS Anti-Lock Braking System Function

The purpose of an anti-lock braking system is to allow the driver to maintain control of the vehicle direction and stability during braking on a variety of road surface conditions and to minimise stopping distance.

ABS Components and Operation

Wheel Speed Sensors and Exciter rings

Wheel Speed sensors measure the rotational speed of individual road wheels from toothed or slotted reluctor rings to produce an electrical signal which is sent back to an anti lock braking system control module.
Wheel speed sensor signal may also be used for road speed measurement.

Brake Pedal Switch

A brake pedal switch signal monitored by the Anti-lock Braking System controller ensures the system is only functional during brake operation.

ABS Control Module and Modulator

The Antilock braking system control module compares the input signals from each wheel speed sensor during braking to recognise if a potential lock up condition may occur.
The ABS control module output function actuates solenoids to regulate the modulator brake control valve hydraulic pressure to the affected wheel to prevent the wheel from locking.

Supply Voltage: The ABS control module can be sensitive to power supply faults including incorrect battery voltage

ABS Warning lamp function sequence

The ABS Warning lamp should illuminate when the ignition is switched on then go out after a system self check has been performed.
Should the ABS warning lamp fail to come on or remain constantly lit during vehicle operation then a system fault may be present.

Computerised ABS System Fault Diagnostics

Modern vehicle ABS may be interrogated using serial diagnostics with a scan tool with suitable software.
Use of either multimeter or oscilloscope may be required for further system signal testing.

A permanently illuminated ABS warning lamp will result in MoT test failure as it may represent a dangerous condition.

Typical ABS Faults

Faulty wheel speed sensors
Rotor ring damaged or dirty rotor sensor ring
Faulty ABS modulator solenoids
Abnormal battery voltage
Brake hydraulic system pressure faults
ABS wiring faults.
Incorrect signals to control units

Brake Pad Fitting

Mobile service for fitting of Brake Pads, Brake disc rotors  , Brake Shoes, Brake Drums, Wheel cylinders, Brake Calipers,  Handbrake cables.

Brake System Computerised Diagnostics