Abs Modulator: Notes
WARNING: This page is about a different car, the 2004 Land Rover Discovery, 2003 Land Rover Discovery, 2002 Land Rover Discovery, and 2001 Land Rover Discovery. However, it is still accessible from the selected car via links, so may be relevant.
The ABS modulator is a 4 channel unit that controls the supply of hydraulic pressure to the brakes in response to inputs from the SLABS ECU. The modulator is attached by three mounting bushes to a bracket on the LH inner front wing, and connected to the primary and secondary hydraulic circuits downstream of the master cylinder assembly. Three electrical connectors link the ABS modulator to the vehicle wiring.
Passages within the ABS modulator, separated into primary and secondary circuits, connect to the various internal components that control the supply of hydraulic pressure to the brakes:
- Shuttle valves and non return valves control the flow through the internal circuits.
- Shuttle valve switches, connected in series to the SLABS ECU, provide a brakes on/off signal.
- A damper chamber and restrictor are included in each circuit to refine system operation.
- Inlet and outlet solenoid valves control the flow to the individual brakes.
- An expansion chamber is connected to each circuit to absorb pressure.
- A return pump is connected to both circuits to provide a pressure source.