Misfire affecting emission levels
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2007 Volvo V70, 2006 Volvo V70, 2005 Volvo V70, 2004 Volvo V70, and 2003 Volvo V70. However, it is still accessible from the selected car via links, so may be relevant.
If the engine control module (ECM) detects a certain number of misfires during 1000 engine revolutions, this is interpreted as misfiring which affects emissions. If misfiring is detected in the first 1000 engine revolutions a diagnostic trouble code (DTC) is stored and the malfunction indicator lamp (MIL) lights. However, if misfiring is detected after the first 1000 engine revolutions, four misfires need to be detected before a diagnostic trouble code (DTC) is stored.