Brakes (ABS sensors): Description and operation

The SLABS ECU continually calculates vehicle speed using the wheel speed inputs from all four ABS sensors. The calculated vehicle speed is then used as a reference against which individual wheel speeds are monitored for unacceptable acceleration or deceleration. The ABS sensor inputs are also used by the SLABS ECU to detect vehicle deceleration rate, vehicle cornering rate and rough terrain.

The engaged forward gear and (on manual gearbox models) the clutch status are computed from the engine data input, the engine speed input and vehicle speed. Reverse gear status is provided by an input from the reverse lamp switch (manual gearbox models) or the BCU (automatic gearbox models). On automatic models, the BCU also provides the neutral selected input.

In addition to controlling the brake related functions, the SLABS ECU: l Controls the operation of the self levelling suspension (SLS) system (where fitted). REAR SUSPENSION, DESCRIPTION AND OPERATION, Description. l On V8 models, outputs a rough road signal to the ECM when traversing rough terrain. l Outputs a vehicle speed signal.

The vehicle speed signal is output to the following systems (where fitted): l Active Cornering Enhancement. FRONT SUSPENSION, DESCRIPTION AND OPERATION, Description - ACE. l Air conditioning. AIR CONDITIONING, DESCRIPTION AND OPERATION, Description. l Cruise control. ENGINE MANAGEMENT SYSTEM - Td5, DESCRIPTION AND OPERATION, Description. ENGINE MANAGEMENT SYSTEM - V8, DESCRIPTION AND OPERATION, Description - engine management. l Engine management. ENGINE MANAGEMENT SYSTEM - Td5, DESCRIPTION AND OPERATION, Description. ENGINE MANAGEMENT SYSTEM - V8, DESCRIPTION AND OPERATION, Description - engine management. l In-car entertainment. IN CAR ENTERTAINMENT, DESCRIPTION AND OPERATION, Description. l Instrument pack. INSTRUMENTS, DESCRIPTION AND OPERATION, Description.

ABS sensors

The ABS sensors supply the SLABS ECU with a sinusoidal speed signal from each wheel. An inductive sensor, installed in the hub bearing of each wheel, senses off a 60 tooth exciter ring integrated into the inner race of the hub bearing. Each ABS sensor has a fly-lead connecting it to the vehicle wiring.