Engine Immobilization

Description
The function of the engine immobilization system is to prevent unauthorized starting of the vehicle. The system is controlled by the immobilization ECU, which is located behind the center of the fascia. 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 barrel.

Operation
Feed from the positive battery terminal (C0192) is supplied to fusible link 1, fusible link 3, and fusible link 4 of the engine compartment fuse box (C0632) on an R wire. Fusible link 4 (C0574) is connected to fuse 13 of the passenger compartment fuse box (C0587) by an NW wire. Fuse 13 (C0583) provides a constant battery feed to the immobilization ECU (C0059) on a PN wire.

Fusible link 3 (C0571) is connected to the ignition switch (C0028) by an N wire. When the ignition switch is turned to the 'auxiliary' position, current flows across the switch (C0028) to fuse 27 of the passenger compartment fuse box (C0588) on a PS wire. Fuse 27 (C0580) provides an auxiliary ignition feed to the Central Control Unit (CCU) (C0430) on an LGW wire.

When the ignition switch is turned to the 'crank' position, current flows across the switch (C0028) to fuse 5 of the passenger compartment fuse box (C0588) on a WR wire. Fuse 5 (C0581) provides a feed to the immobilization ECU (C0059) on a WR wire. The immobilization ECU (C0059) is earthed via the passenger compartment fuse box (C0587) on a B wire.

Immobilization ECU Inputs/Outputs
The immobilization ECU receives inputs and outputs from a number of different components to ensure the right criteria are met before it will allow the engine to be started.

Transponder Coil
The transponder coil (C0049) mounted around the ignition barrel, and is connected to the engine immobilization ECU (C0059) by KB and KG wires. Both connections between the immobilization ECU and the transponder coil switch between both inputs and outputs. The transponder coil reads the vehicle identification information contained within the key transponder and relays it to the immobilization ECU. The immobilization ECU (C0059) then compares this information with the vehicle identification information received from the Central Control Unit (CCU) (C0429) on a G wire.

Central Control Unit (CCU)
The CCU (C0429) outputs a locking status signal to the immobilization ECU (C0059) on a KN wire. If the vehicle has been superlocked or the anti-theft alarm system is armed, the immobilization ECU issues a request for the CCU to remove both before it will allow the engine to be cranked.

NOTE: When the CCU receives a 'remove superlock' signal from the immobilization ECU, it will unlock the driver door. Superlocking will be removed from the remaining doors if single point entry is selected.

The CCU also outputs an ignition status signal, informing the immobilization ECU when the ignition switch has been turned to the 'ignition' position. The CCU (C0428) transmits this signal to the immobilization ECU (C0059) on an ON wire.

Gearbox Solenoid (Automatic Vehicles Only)
When the gear selector lever is in the Park (P) or Neutral (N) position, the gearbox solenoid (C0244) provides a feed to the immobilization ECU (C0059) on a W wire. If the selector lever is moved to any other position, the feed is removed and the immobilization ECU will not allow the engine to be cranked.

Engine Control Module (ECM)
If the correct re-mobilization code is received from the remote handset, the immobilization ECU (C0059) transmits a rolling code to the ECM (C0331 on Td4 vehicles, C0913 on K Series vehicles, C0371 on KV6 vehicles) on a YR wire. The ECM (C0603 on Td4 vehicles, C0913 on K Series vehicles, C0371 on KV6 vehicles) will now energize the main relay by providing an earth path for the relay coil (C0576) on a WK wire.

Starter Relay
If the vehicle has been successfully re-mobilized, the immobilization ECU (C0059) provides a feed to the starter relay coil (C0576) on an RW wire. The relay coil (C0576) is earthed on a B wire. The energized relay allows a feed from fusible link 7 to flow across the relay switch contacts (C0572) to the starter motor (C0179) on an NR wire (NR then B on Td4 vehicles).

Diagnostic Socket
The diagnostic socket (C0040) is connected to the immobilization ECU (C0059) by a K wire, enabling the immobilization ECU to be interrogated by TestBook or T4.