Vehicle Immobilizer Systems - Viper 7900 Installation Manual

Vehicle immobilizer or key cylinder systems
Most new vehicles have a factory engine immobilizer system designed to prevent any unauthorized use
of the vehicle. These immobilizers will cut off power to the starter and the fuel supply preventing a thief
from starting the vehicle.
Some are basic resistance-based systems that require a correct value resistor embedded in the key to start
the vehicle. Other more advanced transponder based systems read a microchip in the key body allowing the
vehicle to start only after it has confirmed the key is valid by the vehicle ECU.
Attempting to start a vehicle without the correct immobilizer bypass can lock up the vehicle ignition or
fuel system causing a potentially expensive trip the dealership.
Refer to the vehicles owners guide to determine if an engine immobilizer bypass module is required before
attempting to remotely start the vehicle.
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