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Juan Crespo
Juan Crespo, Tech Trainer
Category: GMC
Satisfied Customers: 1523
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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2007 GMC Yukon XL Denali. Code P0430. Likely the bank 2 Cat

Customer Question

2007 GMC Yukon XL Denali. Code P0430. Likely the bank 2 Cat but maybe the sensor?
JA: Do you happen to have a code reader or scan tool? What size is your engine?
Customer: Don't have either here. 6.2 l engine
JA: Tell me a bit more about what's going on so he can help you best. Are you hoping to fix this yourself?
Customer: No operating issues. Check Engine ***** *****ght came on and had a reading done at auto supply store to get the cause code. Can't fix it myself as likely will have to cut out old Cat and weld in a new one.
JA: OK! The GMC Mechanic will help you with the diagnostics so you are sure to get this fixed right. Is there anything else important you think the GMC Mechanic should know about your GMC?
Customer: mileage 99,900 miles. no other issues.
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the GMC Mechanic about your situation and then connect you two.
Submitted: 8 months ago.
Category: GMC
Expert:  Juan Crespo replied 8 months ago.

Hi there.

Yes, theoretically the cat could be good and the code could have been set by the downstream sensor sending a signal similar to that of the upstream. However, for that to happen, air would have to be entering the exhaust stream between the cat and that sensor. In conclusion, unless there is a hole in the exhaust pipe, the cat is no longer doing what is supposed to do and needs to be replaced.

Please let me know if you have any other questions.

Customer: replied 8 months ago.
Satisfied with response. Quick and to the point.
Expert:  Juan Crespo replied 8 months ago.

Thank you.

Best Regards.