P0420 - Cat Code ???
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Joined: May 2014
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P0420 - Cat Code ???
Posted in the general forum but not much response, so maybe you tech guys have a better idea. 2014 M7 7K miles. Dealer just rebuilt the manual trans to replace two bad synchros, some rings, gaskets, etc. Got the car back and almost immediately threw a P420 code. Back to dealer, they look over and find no mechanical issues. GM tells them to reset to comp/code, take a long drive, and it appears fine. I take it out two days later and the code 420 CEL pops back on, car running sluggish, loud, probably running rich dumping fuel etc. At the dealer now but no word.
Any ideas?? Could a cat really go bad at 7K?
https://www.corvetteforum.com/forums...bad-at-7k.html
Any ideas?? Could a cat really go bad at 7K?
https://www.corvetteforum.com/forums...bad-at-7k.html
Safety Car
Joined: Jan 2006
Posts: 3,940
Likes: 42
From: shavertown Pa.
http://westersgarage.eidnet.ca/obd2%...le%20codes.pdf
P0420 Catalyst System Efficiency Below Threshold (Bank 1)
P0420 Catalyst System Efficiency Below Threshold (Bank 1)
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Advanced
Joined: May 2014
Posts: 89
Likes: 2
http://westersgarage.eidnet.ca/obd2%...le%20codes.pdf
P0420 Catalyst System Efficiency Below Threshold (Bank 1)
P0420 Catalyst System Efficiency Below Threshold (Bank 1)
Drifting
Joined: Jun 2007
Posts: 1,425
Likes: 238
From: Macomb MI
I recall another member having similar issue. One of the O2 sensors got banged up in an exhaust removal/reinstall. Replaced sensor and all was well. Could also possibly be wiring harness or connector not seated or damaged. They need to drop the whole torque tube assembly for the trans repair, so the exhaust aft of the manifolds comes out. Really easy to smack the O2s the wrong way...
The problem with the other poster is that I believe the O2 was "ok" electrically when scanning, but the guts had been damaged in a way that caused false readings in use. When he removed it stuff was rattling around inside.
edit: found it. Impact wrench killed his O2 and caused the same CEL as the OP. I think the dealer owes you a new sensor...
https://www.corvetteforum.com/forums...post1590289295
The problem with the other poster is that I believe the O2 was "ok" electrically when scanning, but the guts had been damaged in a way that caused false readings in use. When he removed it stuff was rattling around inside.
edit: found it. Impact wrench killed his O2 and caused the same CEL as the OP. I think the dealer owes you a new sensor...
https://www.corvetteforum.com/forums...post1590289295
Last edited by xp800; Oct 20, 2015 at 08:27 AM.
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Joined: May 2014
Posts: 89
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Dealer just called and GM authorized a new Cat replacement. Should be done by EOD and then they said to give it a few days for the CEL to clear. Fingers crossed yet again! But surprising a primary cat could fail soo soon, or was just damaged when they pulled the trans out for synchro repair.
Or maybe I just drive too fast!!
Or maybe I just drive too fast!!
Burning Brakes
Joined: Feb 2010
Posts: 878
Likes: 61
From: Louisa, Ky
Posted in the general forum but not much
Any ideas?? Could a cat really go bad at 7K?
https://www.corvetteforum.com/forums...bad-at-7k.html
Any ideas?? Could a cat really go bad at 7K?
https://www.corvetteforum.com/forums...bad-at-7k.html
