I did an ECU check because my CEL just came on and I got 4 long pulses and 13 short ones. I know the 99 ECU's are a little bit different from the other 4th gens, so how can I find out what my problem is? Is there an ECU decoder site for 99 Maximas?

 

check out this website
http://vbxmaxima.8m.com/ecudecoder.html

 

I know I did. It works great for 95-98 fourth gens but us 99's have a slightly different ECU. That site doesn't even have an option for 13 short pulses. That's why I was asking if there was a list of 1999 Maxima ECU trouble codes.

 

upstream O2 sensor circuit slow response fault (left bank)

 

Thanks, may I ask how you found out?