# 2005 Maxima check engine light codes



## brianj1573 (May 8, 2015)

I have a 2005 Maxima SL with the check engine light on. The two codes that it is giving me are P1273 & P0420. The car is due for an inspection and it won't pass if the check engine light is on. All of the research I've done online, says that it's related to the oxygen sensors. If anyone has dealt with these codes before on a Maxima, I would greatly appreciate your help. The car has already failed inspection after I had a friend help me do some work and clear the codes.


Thank you,
Brian


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## smj999smj (Jan 1, 2006)

The P0420 catalyst code is probably a by-product of the P1273 O2 sensor code. P1273 is the bank 1, upstream sensor. Bank 1 is the rear bank, near the firewall. The sensor is NTK #24320; I usually get O2 sensors from Rockauto.com as the prices are hard to beat and NTK is the OEM supplier of the oxygen sensors to Nissan. Most of the time, it's the O2 sensor that is the cause, however, the only way to be 100% sure is to perform the diagnostic tests outlined in the factory service manual for the code. This link will give you more info on P1273:

P1273 Nissan Air Fuel Ratio Sensor 1 Lean Shift Monitoring Bank 1 OBDII Engine Light Trouble Code | Engine-Codes.com


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## brianj1573 (May 8, 2015)

i have replaced the oxygen sensor and the p1273 code is gone, but i am still getting the p0420 code. the research i've done says that it's the catalytic converter. do i need to replace the catalytic converter now? a friend of mine said that it's had the p0420 code for many years. he would clear the code for me and once i drove 100 miles i could get the car inspected. he cleared the code for me last night and the light came back on after 27 miles. any help would be greatly appreciated.


Thank you,
Brian


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