O2 sensor code P0420 and P0430

CERRILLO

MEMBER
2004 CADILLAC SRX
4.6L
V8
AWD
AUTOMATIC
118,000 MILES

What do I need to change with these codes.
I resentky purchased this car from a local dealership and they said the changed the sensors but did not and now the won't take responsibility for the mess. So I have to fix this car myself after paying them 7000 cash. I want to do it myself to save some cash but I don't know what to replace I've tried google and I have found nothing please help?
I need to know what O2 sensors and where they are located

4 Replies

HMAC300

MECHANIC
48,601 POSTS

Those codes are catalytic converter codes not O2 sensors. You either have an air leak before the converters or the converters are bad. If it is a 4.6L then they are $300 per side if it's a 3.6L it's about $200 per side depending if they are approved for California or not if you live in California. That is price at rock auto. Com

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Wednesday, August 19th, 2015 AT 6:53 PM

CERRILLO

MEMBER
3 POSTS

Are there any other things that I can try before I send $600 more

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Wednesday, August 19th, 2015 AT 9:12 PM

CERRILLO

MEMBER
3 POSTS

Cleaners, O2 sensors, air filter, mass air flow sensor, spark plugs, throttle control?

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Wednesday, August 19th, 2015 AT 9:15 PM

HMAC300

MECHANIC
48,601 POSTS

Rather than trying a new O2 sensor have a mechanic see if they are operating ok if they are it's your converters if there is no air leaks in exhaust system prior to converters. There are one O2 sensor for each side in front of converter so if you bought them and it's still the converter and you are wasting your money

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Thursday, August 20th, 2015 AT 5:33 AM