Method for diagnosing presence of exhaust gas after-treatment device and use of on-board diagnostic technology

摘要

In a method for diagnosing the presence of an internal combustion engine exhaust aftertreatment component on a vehicle, the exhaust temperature is measured downstream the aftertreatment component continuously over a time period to provide a first temperature signal with fluctuating amplitude. The temperature signal is modified to provide a second modified temperature signal. The first and second temperature signals are compared to detect any significant difference between the signals.