P0420 and p0430 after new cats and 3 of 4 o2 sensors


P0420 and p0430 after new cats and 3 of 4 o2 sensors Mechanic's Assistant: Have you located all of the vehicle's oxygen sensors? Are the wires leading to and from each intact and in good shape? Yup Mechanic's Assistan...

P0420 and p0430 after new cats and 3 of 4 o2 sensors Mechanic's Assistant: Have you located all of the vehicle's oxygen sensors? Are the wires leading to and from each intact and in good shape? Yup Mechanic's Assistant: What is the make/model/year of your car? 10 enclave Mechanic's Assistant: What year is your Enclave? 2010. New motor and transmission 900 miles. Mechanic's Assistant: Are you fixing your Enclave yourself? What have you tried so far? Had the 430 before engine change

Automotive Expert
Hello, Welcome to Just Answer My name is \*\*\*\*\* \*\*\*\*\* I've been an automotive engineer since 1996 and together we're going to solve this issue. to still get that code with new cats and sensors then either its burning a lot of oil but I'd say its more likely that the wiring between the O2 sensor and the ECM is faulty as if you have anything more than 3 ohms then this will offset the signal and give errors so the next step should be to measure the wire continuity between the O2 sensor socket and ECM socket to ensure it has no high resistance

I wouldn't think this would happen on both banks at the same timeWouldn't think this would happen on both banks at the same time
Automotive Expert
Well if the correct section of wiring harness is damaged / shorted out then yes you can have both faulty O2 signals back to the ECM

Ok I'll check thanks
Automotive Expert
Hi how did you get on ? If you need more information from me to complete the answer please ask

Didn't get to check yet, sometime this week.
Automotive Expert
Understood

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