Power and Ground Distribution: Description and Operation

ENGINE IMMOBILIZATION

DESCRIPTION

General
The function of the engine immobilization system is to prevent unauthorized starting of the vehicle. The system is controlled by an immobilization ECU which is located beneath the centre console, adjacent to the handbrake. Re-mobilization is achieved via a transponder in the vehicle key, which is read by a transponder coil when the ignition switch is turned to the 'auxiliary' position. The transponder coil is mounted around the ignition switch.

OPERATION

V8

Power Distribution
Feed from the positive battery terminal (C0192) is supplied to the following on an R wire:
- Fusible link 2.
- Fuse18.
- Fuse25.
- Fuse53.

All are located in the passenger compartment fuse box (C0632).

Fusible link 2 (C0591) provides a constant battery feed to the immobilization ECU ('20059) on an R wire. Fuse 18 (C0584) provides a constant battery feed to the immobilization ECU (C0059) and the steering column interlock ECU (C2055) on a pair of RY wires.

Fuse 53 (C0583) provides a constant battery feed to the ignition switch (C0028) on an R wire. When the ignition switch is turned to the 'auxiliary' position, current flows across the switch (C0028) to fuse 39 of the passenger compartment fuse box (C0585) on a PB wire. Fuse 39 (C0587) provides an auxiliary ignition feed to the immobilization ECU (C0059) and the steering column interlock ECU (C2055) on a pair of PB wires.

When the ignition switch is turned to the 'ignition' position, current flows across the switch (C0028) to fuse 31 of the passenger compartment fuse box (C0585) on a G wire. Fuse 31 (C0587) provides an ignition feed to the steering column interlock ECU (C2055) on a GB wire.

Fuse 25 of the passenger compartment fuse box (C0583) provides a constant battery feed to the ignition switch (C0028) on an RU wire. When the ignition switch is turned to the 'crank' position, current flows across the switch (C0028) to the Engine Control Module (ECM) (C0331) on a BY wire.

Steering Column Interlock ECU
The steering column interlock ECU (C2055) receives the following power supplies:
- A constant battery feed from fuse 18 of the passenger compartment fuse box (C0584) on an RY wire.
- An auxiliary ignition feed from fuse 39 of the passenger compartment fuse box (C0.587) on a PB wire.
- An 'ignition on' feed from fuse 31 of the passenger compartment fuse box (C0587) on a GB wire.

The ECU is earthed on an NB wire.

Transponder Coil
The transponder coil (C0049) is connected to the immobilization ECU (C0059) by YU and YN wires. Both connections between the immobilization ECU and the transponder coil switch between being both inputs and outputs. The transponder coil reads the vehicle identification information contained within the key transponder and relays it to the immobilization ECU.

Immobilization ECU
The immobilization ECU (C0059) is located beneath the centre console, adjacent to the handbrake. It receives a constant battery feed from fuse 18 of the passenger compartment fuse box (C0584) on an RY wire, and an auxiliary ignition feed from fuse 39 of the passenger compartment fuse box (C0587) on a PB wire.

If the immobilization ECU (C0059) has received a valid signal from both the transponder coil (C0049) and the steering column interlock ECU (C2055) where the ignition switch is turned to the crank position, it transmits a rolling code to the Engine Control Module (ECM) (C0331) on a BP wire.

The immobilization ECU (C0059) also provides a feed to the interlock relay (C1455) on a B wire. The energized interlock relay (C1455) provides a feed to the starter motor relay (C0179) on a B then BY wire.