My g35 03 130k has failed the smog test. The code is p0057. I replaced both downstream with NTK. I also checked all wiring and fuses and they are fine. I was forced to go to 4 mechanic shops including the stealership. One mechanic told me i might need new catalyc converters but her is not sure it will fix the problem. The other said to contact the stealeship. The stealership said its an electrical problem and i might need a new ECM. Anyone has a similar problem? Ive spent too much trying to fix it and would like advice before i purchase and install an ECM.

 

Do you have any modifications? Did you check voltage and resistance to the o2 sensor? Are your battery terminals fastened (you'd be surprised)?

Good troubleshoot guide is here http://www.obd-codes.com/p0057

 

I had my mechanic check the voltage. Is outputting lower than the others. The battery os good. Thanks for the website! It still hasn't fixed the problems.

 

Is your car tuned? Sometimes the tuner will disable the o2 sensors if you're running test pipes.

 

Its can tuning i think the brand was cobb. I went to an infiniti specialist mechanic and he told me my ecu is wrong. I have an ecu for a sedan and i need one for coupe. The programming number goes:

After programing: 23710-am607
Before programing: 23710-am606

He was able to pass the smog test but did not fix my check engine light which i would like to fix. Im not sure what these mean so i would like to know if i need to buy a new ecu or if he can program the one i have.