ABS Wiring and Operation

1. Disc


2. Rear Wheel Sensor


3. Toothed Rotor

4. Hydraulic Module

5. Brake Master Cylinder

6. Rear caliper

7. Brake Booster

Wiring Diagram Practice


There are a number of components in the ABS systems that are also used for fuel injection. These are mostly speed sensors e.g. wheel speed and engine speed



Using the diagram in the workshop manuals identify the wheel speed sensors and list their wire colours for each sensor.



Front Right: B/W



Front Left: G/R

Rear Left: L/P

Rear Right: Y/BR

On the ABS wheel sensor what is the reason for the braded wire?

So it can be used for shielding purposes or used alone in flattened form as a shielding strap (ref There are many advantages of using braded wire for the wheel sensor. ref www.answers.com/topic/braided-wire

• Power: Braded wire can carry more power because it has a higher surface area. It can also used to carry large amounts of power because it dissipates heat much quicker when there is space between the wires.



• Sound: When sound is introduced to a piece of wire, a vibration occours, disrupting the signal. This is bad for the wheel sensor because the sensor is constantly operating and sending signals to the ECU. With braded wire, voltage gets dissipated alot quicker as the signal is sent to the ECU.



• Flexibility: Braided wire is often used for devices that need to be compact because of it's greater flexibility. This is a great advantage because the hose is constantly moving and twisting and braided wire is much more reliable.

Identify and list all the fuses that are used by the ABS circuit.

F14 fuse box, FL main, Y-G, Gauge 10A, Dome 20A, Stop 15A (brake) and ECU.

Identify the earths for the ABS control unit and ABS motor and their wire colours and pin numbers

10B W-B/ 7B W-B/ 1A W-B

On the wiring diagram for the ABS actuator, identify which solenoids control which wheel cylinder. Then note the wire colours and pin numbers.

Front Right Wheel Pin Number: 2B/6B Wire Colour: R-W/R-G

Front Left Wheel Pin Number: 3B/ 7B Wire Colour: L-R/ L-W

Rear left Wheel Pin Number: 1B/5B Wire colour: BR-W/BR-R

Rear Right Wheel Pin Number: 4B/8B Wire Colour: G-B/ G-Y