Had a Trouble Code today that said something like 'System too lean- Bank One' Can someone pls tell me what this is refering to? If I remember correctly the code was 171. Vehicle is a 96' Camaro V6, 3.8L. Thanks for any help
Win
I'm not sure I understand your question, because the Diagnostic Trouble Code (DTC) is pretty self-explanatory.
DTC P0171: System too lean (Bank 1)
It says the system is too lean on bank 1...
A V configured engine has two banks of cylinders (left and right). This problem is on "Bank 1".
"Too lean" means the O2 sensor on (bank 1, in this instance) is sending a high voltage signal (consistently higher than .450v) to the PCM, indicating a lean AFR condition. Lean means, too much air or not enough fuel.
The Oxygen (O2) sensor measures *oxygen* in the exhaust system as a indication of Air/Fuel (A/F) mixture or Air Fuel Ratio (AFR). High O2 content = Lean condition (too much air) Low O2 content = Rich condition (not enough air)
BTW, a high O2 content in the exhaust doesn't necessarily mean there is a true lean condition. A engine misfire will also cause a high O2 condition because the oxygen in the offending (misfiring) cylinder isn't being burned like it would be if there were no misfire. That in turn will cause a false reading for the PCM. The PCM can't tell if the high O2 content is caused from a engine misfire or a (true) lean condition (plugged injector, vacuum leak, etc.). The same thing applies with a exhaust leak. If a exhaust manifold flange gasket is leaking, it will allow fresh air into the exhaust system, the O2 sensor sees excess O2 and tells the PCM that there is a lean condition on that bank.
So don't just assume it's lean. It may very well be but you still don't just jump to the conclusion that it is. The first step in diagnosing electronic engine controls is checking the *basics* before jumping into the electronics.
Been a long time, Preacher
Could also be a bad sensor. I read something a while back about the O2 sensor. Someone correct me if I'm wrong. I read that it basically measures heat. Too lean means the exhaust will be hot, too rich it will be cool. A perfect mixture makes the sensor happy. I tend to agree with this as I find it hard to believe that a small device stuck in the exhaust pipe can accurately measure oxygen content. Bill
Sorry, but your explanation is inaccurate. The oxygen sensor uses an element that generates a voltage when it senses oxygen. The only thing heat has to do with it is that the sensors need to be heated above 600*F to function properly. The O2 sensor will flucutate from lean to rich, temperature will never fluctuate as quickly as an O2 sensor registers crosscounts.
-Bruce
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