Abstract: A method and apparatus for detecting abnormal behaviour in a vehicle (8) with an engine having engine control module includes providing a database (20), and a vehicle analyser (12) having a communication device (16) and an interface (14) that links the communication device (16) to a vehicle (8). Engine parameters that are retrieved through the interface (14) during driving experience are uploaded to the database (20) using the communication device (16). The database (20) analyses the engine parameters from multiple driving experiences to establish historical data and determine normal operation of particular retrieved engine parameters based on the historical data. A vehicle (8) can be diagnosed by comparing its retrieved engine parameters with the database (20).