Secondary Ignition Circuit
WARNING: This page is about a different car, the 2009 Dodge Sprinter. However, it is still accessible from the selected car via links, so may be relevant.
The PCM cannot detect an inoperative ignition coil, fouled or worn spark plugs, ignition cross firing, or open spark plug cables. The misfire will, however, increase the oxygen content in the exhaust, causing the PCM to store an oxygen sensor, fuel system, or misfire diagnostic trouble code. Also see misfire detection.