2003 Maxima will not pass smog
#1
2003 Maxima will not pass smog
I have 2003 Maxima that will not pass smog in California. Error code that shows it is 02 censors we have changed them and the computer then drove it 100 miles now it is coming up 02 censors again? 02 censor’s volt readings are above normal. The latest smog test showed gross polluter EGR valve working correctly. This vehicle has been to 5 different shops and can’t find the problem can anyone help!
#4
Not sure took it to the garage they changed out the ones that they said were bad. They also check the 02 censors by directly bypassing the computer. The censor readings were normal but when you hook it up to the computer the reading are well above normal so we changed the computer now we are getting the same readings.
#9
If the A/F O2 sensor voltage output is high as you say, then the exhaust oxygen content is low which indicates a rich mixture. A rich mixture consumes nearly all the oxygen. It could be excessive fuel pressure or the fuel injectors are leaking big time or extreme back pressure.
#13
Excessive Oxides of Nitrogen is caused by anything that makes combustion temperatures rise. The EGR system plays a big part in cooling combustion temperatures. Could be a plugged EGR passage, EGR valve failure, leaky EGR vacuum hose. Also an excessively Lean air/fuel mixture will cause elevated temperatures. Cooling system problems can also contribute to this issue.
If you ever ran the car for an extended time with bad coils generating misfires, then the CATS are probably gone. You never indicated if you are throwing any OBD fault codes. If there were fault codes why would the shop put it on the ASM test.
If you ever ran the car for an extended time with bad coils generating misfires, then the CATS are probably gone. You never indicated if you are throwing any OBD fault codes. If there were fault codes why would the shop put it on the ASM test.
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