Operation

Ignition And Shift Interlock Operation

Ignition interlock
A feed from fuse 20 in the passenger compartment fusebox is connected on a P wire to header C0289 LHD/C0294 RHD. From the the header the feed is connected on P wires to the key interlock unit. The feed is connected within the key interlock unit to the ignition switch illumination and the ignition key inserted switch.

When a door is opened or the vehicle is unlocked using the remote handset the BCU provides an earth path for the ignition switch illumination. The earth path is from the interlock unit on a PU wire to pin C0663-9 on the BCU via header C0285 LHD/C0294 RHD. The completed earth path allows the feed from fuse 20 in the passenger compartment fusebox to illuminate the bulb.

When the ignition key is inserted in the ignition switch, the ignition key inserted switch is tripped and allows the feed from fuse 20 in the passenger compartment fusebox to flow through the switch contacts. The feed is connected from the key interlock unit on a WP wire to pin C0662-2 on the BCU, via header C0293 LHD/C0289 RHD. This provides a signal to the BCU that the key is inserted.

A feed from fuse 21 in the passenger compartment fusebox is connected on a PB wire to the key interlock unit The feed is connected within the interlock unit to the ignition key in position 0 switch.

When the key is inserted in the ignition switch the switch contacts close allowing the feed from fuse 21 to pass on an OW wire to the interlock solenoid If the transmission is in a position, other than PARK, the BCU will supply an earth path for the key interlock solenoid on a BLG wire. The solenoid will energise and removal of key from the ignition switch is prevented.

Shift interlock
The shift interlock solenoid is normally in a de-energised state. When the transmission is to be moved from the PARK position the ignition must be on and the brake pedal depressed This energises the solenoid and allows movement of the transmission selector

When the brake pedal is depressed the feed from fuse 25 in the passenger compartment fusebox flows through the brake pedal switch contacts and is connected to BCU pin C0661-7 on a GP wire via header C0287 LHD/C0290 RHD.

This feed signals the BCU that the ignition is on and the brake pedal is depressed. The BCU sends a signal on an SK wire, via header C0293 LHD/C0292 RHD, to the IDM The IDM in turn provides an earth path for the interlock relay in the passenger compartment fusebox, energising the relay coil and closing the relay contacts.

With the relay contacts closed a feed from fuse 21 in the passenger compartment fusebox flows through the relay contacts and from the fusebox to the shift interlock solenoid on a LGP wire, energising the solenoid. The shift interlock solenoid is connected to earth header C0552 LHD/C0708 RHD on a B wire.

With the shift interlock solenoid energised, the transmission selector can be moved from the PARK position. When the brake pedal is released the feed to the BCU is removed and the shift interlock solenoid is de-energised. The locking mechanism controlled by the solenoid will lock the transmission selector once it is returned to the park position.

Automatic transmission selector
A starter / inhibitor / reverse lights switch is located on the gearbox and is used to inform related components of the gear selector position. The connection used on this circuit is on an NP wire from the switch to pin C0663-10 on the BCU and signals the BCU of PARK and NEUTRAL selector positions.

Transmission neutral sensor
The transmission neutral sensor provides an earth signal to the BCU when the transfer box is in neutral. The earth signal causes the BCU to operate an audible warning to warn of the transfer box in neutral when the ignition is on.

The sensor is connected on a BK wire from pin C0662-15 on the BCU. The sensor is connected on a B wire, via header C1002 to earth header C0552

Transfer gearbox interlock solenoid
When the BCU senses that the ignition key is removed from the ignition switch it signals the IDM via the serial data bus. The IDM then grants an earth path for the coil of the transfer box relay in the passenger compartment fusebox, energising the relay coil and closing the relay contacts

With the contacts closed a feed from fuse 21 in the passenger compartment fusebox passes through the relay and is connected from the fusebox on an RU wire, via header C0293, to the transfer gearbox interlock solenoid. The solenoid energises and is connected by a B wire to earth header C0552. This prevents neutral being selected locking the transfer gearbox in high or low A diode is located in the feed to the solenoid from splice joint A77 on an RU wire and from the diode to splice SJ2 on a B wire. The diode prevents residual current causing the solenoid to 'stick in the energised position