Secondary Ignition Circuit

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, deceiving the PCM in to thinking the fuel system is too lean. Also see misfire detection. There are DTC's that can detect misfire and Ionization shorts in the secondary ignition circuit, refer to the appropriate POWERTRAIN CONTROL MODULE (PCM) - ELECTRICAL DIAGNOSTICS - 40TE AUTOMATIC TRANSMISSION or POWERTRAIN CONTROL MODULE (PCM) - ELECTRICAL DIAGNOSTICS - 62TE AUTOMATIC TRANSMISSION for more information.