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Old 01-09-2018, 11:46 AM
Mr.L Mr.L is offline
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1996 Maxima
2006 Frontier
Join Date: Jul 2016
Location: Torrance
Posts: 8
Default Fuel control feedback question


Mine is a 2006 Frontier, 4L, I've owned about 18 months. Both CATs were changed when I bought the truck. According to my wonderful BlueDriver Christmas present there are no codes, pending or otherwise. The truck runs very well and aside from an annoying deep vibration (about 60 Hz) that sets in when the idle drops below about 600 rpm, which it does on occasion, I've no complaints.

My concern probably stems from having too much information from the BlueDriver. When I use the Live option and monitor Fuel System Status, I get the result: System A: closed loop, using all oxygen sensors... and System B: open loop - has yet to satisfy conditions to go to closed loop (Bank 1, or both).

Questions: 1) just what is System A, and System B? I can't find the answer to this despite some considerable effort. 2) If part of the fuel system is not going to the desired closed loop condition, then shouldn't there be a code and shouldn't the BlueDriver say the will truck fail smog, which it does not say. In fact, it says the truck is ready for smog check.

I did check the O2 sensor #1 for each bank and for bank 1 the O2 sensor has a very different (lazy) pattern than that on bank 2. I have no records that the sensors have ever been changed so I'm considering just changing them least the upstream sensors. Sensor #2 on each bank seem fine.

Thanks for any insight anyone can offer on this. And if anyone is in the market for a really good OBD reader, the BlueDriver is a pleasure to use.

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