Will the SES light shut off by itself?
Just in case it matters, the car threw the 420 code for bad cats/O2 sensors/etc..
I'm in the process of changing out the spark plugs, possibly the O2 sensors and if that doesn't work...the cats.
Thanks!
The PCM will illuminate the Malfunction Indicator Lamp (MIL) during the first trip in which the diagnostic test has been run and failed.
The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data.
CONDITIONS FOR CLEARING THE MIL/DTC
The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
The DTC can be cleared by using a scan tool.



