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Erasing trouble codes

4022 Views 3 Replies 4 Participants Last post by  danog
On my '06 DTS I have a P0420 after a 40 minute idling while looking at Christmas lights. Would disconnecting the battery and grounding the positive cable (to discharge the capacitors) erase the trouble code? My Cadillac dealer wants to reprogram the PCM at a cost of $144. The car runs great and gets excellent gas mileage.
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Pretty much what Submariner409 said...
It may just need some good old fashioned HARD DRIVING...

Here is a little info on the code...
P0420 Catalyst System Efficiency Below Threshold (Bank 1)

The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. The downstream O2 sensor reading should be fairly steady. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar.

This is indicative of (among other things) a converter that is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.
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