2. Immobilizer, cars with diesel engines: Notes

Fig 1: Identifying Bus Function Chains - Immobilizer (Cars With Diesel Engines)

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Fig 2: Identifying Bus Function Chains - Immobilizer (Cars With Diesel Engines)

Courtesy of SAAB-SCANIA OF AMERICA, INC.

When the ignition is turned on, the TWICE checks that the right key is inserted in the ignition switch. A circuit built into the remote control part of the key sends a code by means of inductance to a coil round the ignition switch under the center console. The code is passed on to the control module, which checks that it is correct. The TWICE also checks that the right MIU is fitted in the car. The MIU continuously sends out an ID number on the bus.

If the key and the MIU identification number are OK, TWICE will send the message "Immobilizer OFF" on the bus.

The immobilizer information is used directly by the engine control module on cars with diesel engines.