P0171 Check Engine Code on 2000 Toyota Corolla
So the P0171 check engine code seems to be a rather popular code. I’ve searched the web quite a bit and most people who see the “Check Engine” light come on their Corolla have this code. It seems that this code usually comes up after the car has been driven 70,000-80,000 miles.
Common advice on the internet suggests that you clean the mass airflow sensor and see if that fixes the problem. The problem could also be caused by a faulty oxygen sensor or a vacuum leak. The corolla has two oxygen sensors. I haven’t looked to see where they are located but one is probably in the exhaust manifold and the other is after the catalytic converter.
So what is the cause of my P0171 error code? I don’t know. The ODB-II reader I used was one that is only capable of checking engine codes. I’m thinking about buying this reader because it should allow me to run the engine and actually look at the output of each of the sensors. I’ve tried listening for a vacuum leak but I don’t hear one. Of course, that doesn’t mean that one doesn’t exist. I just hope I don’t have to replace too many sensors, they are about $100 each.
- Faulty front heated oxygen sensor
- Ignition misfiring
- Faulty fuel injectors
- Exhaust gas leaks
- Incorrect fuel pressure
- Lack of fuel
- Faulty Mass Air Flow (MAF) sensor
- Incorrect Positive Crankcase Ventilation (PCV) hose connection
