Operation

OPERATION

Power Distribution

Feed from the positive battery terminal (C0192) is supplied to fusible link 1 and fusible link 5 of the under seat fuse box (C0632) on an N wire. Fusible link 1 is connected in series with fusible link 4 and fuse 1, which are also located in the under seat fuse box. Fuse 1 (C0573) provides a constant battery feed to the ABS ECU (C0504) on an NW wire. Fusible link 4 (C0571) provides a constant battery feed to the ABS modulator pump relay (C0508) on an NW wire.

Fusible link 5 (C0570) is connected to the ignition switch (C1043 on LHD, C0028 on RHD) by an NW wire. When the ignition switch is turned to the 'ignition' position, current flows across the switch (C1732 on LHD, C0094 on RHD) to fuse 11 of the passenger compartment fuse box (C0580) on a W wire. Fuse 11 (C0580) provides an ignition feed to the ABS ECU (C0504) on a GO wire.

Wheel Speed Sensors

The wheel speed sensors provide the ABS ECU with 60 pulses per wheel revolution. Each wheel speed sensor is connected to the ABS ECU via a twisted pair of wires, with both wires carrying the pulsed signal to the ABS ECU. The sensors are connected to the ABS ECU (C0505) as follows:

The LH front wheel speed sensor (C0516) is connected to the ABS ECU via a pair of W wires. The RH front wheel speed sensor (C0517) is connected to the ABS ECU via a pair of G wires. The LH rear wheel speed sensor (C0502) is connected to the ABS ECU via a pair of W wires. The RH rear wheel speed sensor (C0503) is connected to the ABS ECU via a pair of G wires.

ABS Modulator Pump

The ABS modulator pump is part of the modulator assembly, and is controlled by the ABS ECU. The pump is used to increase brake line pressure. The ABS ECU (C0506) provides a feed to the modulator pump relay coil (C0508) on a WO wire. The relay coil (C0508) is earthed on a B wire. The energised modulator pump relay (C0508) allows a battery feed from fusible link 4 of the under seat fuse box (C0571) to power the modulator pump (C1587 on LHD, C0507 on RHD) on an NR wire. The pump is earthed on a B wire.

The energised modulator pump relay (C0508) also provides a feed to the ABS ECU (C0504) on an NR wire. This feed is used by the ABS ECU to monitor operation of the modulator pump.