ISO 11451-4:2006 specifies bulk current injection (BCI) test methods and procedures for testing the electromagnetic immunity of electronic components for passenger cars and commercial vehicles regardless of the propulsion system (e.g. spark-ignition engine, diesel engine, electric motor). The electromagnetic disturbance considered in ISO 11451-4:2006 is limited to continuous narrowband electromagnetic fields. Part 1 of ISO 11451 gives definitions, practical use and basic principles of the test procedure.