Anti-Lock Brake System (ABS)


Maintaining directional control during heavy braking

ABS / DSC Problems

ABS Warning Lights or DSC Warning Lights illuminating are likely to a fault on the system.

ABS / DSC Diagnosis

At DIAGNOSTICS.WALES we can accurately diagnose the cause of the problem and recommend the most appropriate solution.

ABS / DSC Repairs

Once the specifics of the fault are identified we offer competitively priced repair solutions.

ABS System Components

  • ABS Hydraulic Pump
  • ABS Electronic Modulator
  • ABS Wheel Speed Sensors
  • ABS Reluctor Rings
  • ABS Wiring
  • DSC Module

ABS Hydraulic Pump / ABS Modulator

On most models the ABS Modulator is attached to the ABS Hydraulic pump. Unfortunately faults are fairly common.

Common Error Code Information relating to a pump fault

  • BMW Error Codes 5D50 or 5DF1
  • Multiple Pressure Sensor Faults
  • No Communication with ECU possible
  • Pump motor malfunction

On some models there is a genuine OEM repair kit avalable for the modulator part of the unit. On other models the part is only sold as a complete pump unit which can be expensive.

We offer the alternative of having the unit reconditioned and rebuilt. This is significantly cheaper but has a time implication of approximately ten days off the road.

The process starts with diagnosis and confirming that the pump is the cause of the problem experienced.

ABS Wheel Speed Sensors

There is a wheel speed sensor on each wheel which records the data of the wheel speed and motion by counting the number of slots in the reluctor ring and calculating the data from the speed of completion.

The sensors do fail from time to time with corrosion, damage from road debris or damage from a corroded reluctor ring.

At DIAGNOSTICS.WALES we can run live data from the wheel speed sensors to determine what is happening and assess for a faulty sensor accordingly. If the sensor is found to be faulty we can source, supply & install an OE approved new sensor.

ABS Reluctor Rings

Reluctor rings run the circumference of the driveshaft and have a set number of slots for the ABS sensor to use as a reference for speed calculations and wheel data.

Unfortunately the location of the rings on the driveshafts open to the elements and salty road spray menas that both the driveshafts and the reluctor rings develop corrosion.

The reluctor rings eventually swell and deform to a point where the sensor data collected is so far out of expected tolerance levels that an error code is triggered for the sensor. However it may not be the sensor that is faulty, it may be the corroded reluctor ring.

The BMW approved solution to a corroded reluctor ring is to replace the entire driveshaft(s) which come with shiny new reluctor rings. Unfortunately they also come with a hefty pricetag. We offer an alternative solution which is to remove the old reluctor rings, decorrode the driveshaft and install a new reluctor ring to the original driveshaft at a fraction of the cost.

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