The increasing complexity of electrical functions embedded in automotive and aeronautic applications increases the duration of the EMC qualification tests and the risk of nonconformity. The cost of certified means and skilled personnel for a normative test in radiated immunity are high and are often a bottleneck for the electronic suppliers. Any late-detected EMC non-compliance leads to an increased costs. To solve their problem, electronic suppliers need fast, economical and easy-to-use investigation tools. The Near Field Scan Immunity (NFSI) method developed for Integrated Circuits (IC) testing seems to be a good solution to perform quick investigation at Printed Circuit Board (PCB) level. Some specific probes must be designed and their capability to induce the same failures as during a far field test must be checked. This paper presents a methodology to achieve that point giving some examples of probe's validation.