MaxMike93

So yesterday I got P0420 on my '00 I30. I did some reading up and there is a service bulletin about reprogramming the ECM. The service records I have from Infiniti do not say that the bulletin was done. I was wondering if it was older ECMs that are affected since my car was made in 9/99, so I'd think it was an early production model. Guess I have to take it to the dealer since the ECM is behind the radio, and I wouldn't even know if the P/N is visible once I get everything out. Just hoping that it's the ECM and not the precat/O2 sensor, especially since I have about 40,600 miles right now

Infi30t

You would be better off if it was a sensor.

MaxMike93

The code relates to the sensor that is in the downpipe at the precat, which is something I would rather not do. Although the TSB mentions that the ECMs that require the programming misdiagnose the issue that triggers the SES light. I had the code cleared and will see if it comes back on. If it does, I saw how to check the ECM so I can do that, otherwise I guess it's a trip the the Infiniti dealer for me and my I30