Q: Check engine light, p0171 and p015B codes, what would be a sign of PCV damage vs. O2 sensor damage?

asked by on July 16, 2017

I tripped a CEL 10 minutes into driving while accelerating. This car had a PCV / manifold replacement at 72000 for a known defect. The error codes for today's CEL were p0171 (Lean Bank 1) and p015b (02 sensor delay, b1s1). Knowing that a damaged pcv valve can trip the first code, is there a way to know that the pcv needs replacing before purchasing a new part? The vehicle runs well, occasionally has trouble accelerating with A/C on, but is otherwise running normally. Could the error codes be easily diagnosed another way (i.e. if it's a fuel injection issue or an 02 sensor problem). Thanks for your help, I may end up having you all come take a look.

My car has 117500 miles.
My car has a manual transmission.

Hi there. The P0171 code means that, on the first bank of the engine, the fuel system is running weak or a vacuum leak exists near this side of the engine. A lean condition occurs when the engine either receives too little fuel or too much air. The first thing I would recommend is reading this article on the P0171 OBD-II trouble code, so you can review all of the possible sources of this code (as it’s not as simple as an O2 sensor or PCV valve). It would be a good idea to have a professional mechanic complete a warning light inspection to help isolate the source of these codes and recommend the right repairs.

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