IMMO guideBuying a Used Car With One Key

This guide explains how a vehicle immobiliser (IMMO) system works and why buying a used car with only one key is a financial and practical risk that must be assessed before purchase. It is written for lawful owners and professional technicians who need to understand ownership documentation, choose between dealer and registered automotive locksmith routes, and budget realistically for a spare key. You will learn how to verify that every supplied key starts the car, how to confirm the key count with a diagnostic scan where supported, and how to spot signs of tampering or missing keys. The guide also covers what happens during key programming, how to validate the finished job, common failure modes, scam avoidance, and steps that prevent a repeat of the one-key problem.