9-3 Viggen Coupe (9400) L4-2.3L Turbo (B235) HO (1999)
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2. Immobilization, Viggen
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 centre 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's ID number are OK, the TWICE sends out an "Immobilization OFF" message on the bus. The Trionic T7 acts on this
information by cancelling fuel shut-off, which is always activated whenever the ignition is turned on.
Diagnostics
If the TWICE, MIU or Trionic control module is changed, immobilization must be reprogrammed in the TWICE. If this is not done, the engine will
not start and a diagnostic trouble code will be generated in the Trionic T7.
If the diagnostic trouble code is generated even though programming has been performed, fault diagnosis must be carried out on the immobilization
function in the TWICE.
2. Immobilization, other models
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 centre 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 transmit the message "Immobilizer OFF" on the bus.
The information is used by MIU, which sends it on the K lead to Trionic/Motronic. The engine management system then cancels the fuel shut-off,
which is always activated on every time the ignition is turned on.
The immobilizer function is used by EDC 15 directly on cars with diesel engines.
Diagnostics
