Check Engine Light & Diagnostics
While it’s impossible to say exactly why a check engine light is on or flashing without being able to examine the vehicle and perform a car diagnostic, possible causes of a steady or flashing check engine light can include: Failing oxygen sensor. A loose gas cap. Bad spark plug/ignition coil.
OBDII testing uses a scan tool that plugs into the vehicle’s computer and determines that the emission system and components are working properly. The test downloads stored information from the vehicle’s computer to identify emission systems or components that are not working properly.