The MK70 ABS system will be installed from 05/2004 in vehicles which only have one ABS function.
Vehicles with ESP/Brake Traction Control System (BTCS) will continue to be equipped with the MK60.
The MK60 ABS has been designed specifically for small to medium size vehicles. Compared to the MK20 ABS system, it has been possible to reduce the size of the hydraulic and electric components (e.g. hydraulic valves and solenoids) and the housing.
As a result, the overall weight of the ABS hydraulic unit has been significantly reduced.
The hydraulic unit consists of the pump motor, the valve block with 8 hydraulic valves and the electronic control unit.
The ABS control unit actuates the ABS warning lamp in the instrument cluster via the CAN databus.
The MK60 ABS is a 4/3 system. This means that the wheel speed is measured individually for each wheel (4 wheel speed sensors).
ABS controlled braking is provided individually for the front wheels and jointly for the two rear wheels (3 control channels; select-low control), i.e. the ABS control for the rear wheels is governed by the wheel closest to locking up.
Wheel speed sensors
NOTE: The wheel speed sensors must not be checked for voltage with an ohmmeter.
The wheel speed sensors are active sensors. They are supplied with a voltage from the ABS control unit after the ignition is switched on.
The pulses are picked up from a mechanically encoded ring, which is built into the wheel bearings on the front wheels while for the rear wheels it is a metal ring which is mounted on the stub axle.
The registered wheel speed is converted into a digital (square-wave) signal by the electronics integrated in the sensor and is then transmitted to the ABS control unit.
Data transmissions to the ABS control unit take place via a 2-stranded connecting cable.
It also supplies the vehicle speed signal, which is calculated from the wheel speed sensor signals. This is transmitted via the CAN bus to the Powertrain Control Module (PCM)
The ABS control unit can be diagnosed via the Data Link Connector (DLC).
The hydraulic unit is pre-filled for service.
