Just a generic reader from a parts shop or something like a bluetooth reader that displays on the phone? P0171 usually means that the air/fuel ratio is too lean. Were any other codes thrown besides P0171?
Its a OBD reader I bought on ebay for around 5$ & it connects to my phone via Bluetooth. Air/fuel ratio ? So what do I replace? No other codes Posted via the PriusChat mobile app.
Only fault light that has been on was check engine light? If there really are no other codes then you either have to check life data to figure out where the problem is or just ques something. Maybe cleaning the mass air flow sensor would be a good way to go if it has not been cleaned for long time.
Read on abou other threads where they look for throttle body ..maf sensor and many other parts that are related to figure this you have.... Generic obd readers are not very good for hybrid Posted via the PriusChat mobile app.
Look for something letting unmetered air into the engine, downstream from the throttle body, like a loose PCV hose, a failing O-ring on the engine oil cap or oil dipstick, or a bad throttle body gasket. Clean the mass air flow sensor as previously suggested. If all of this is good, you might have a problem with a fuel injector being clogged. What is the odometer reading?