Check engine light came on.does anyone know what P0171 code from AutoZone means? 02 R53 JCW.Thanks

 

The following is what I found doing a search..

A code P0171 may mean that one or more of the following has happened:

*The MAF (Mass Air Flow) Sensor is dirty or faulty Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled.

*There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.

*There could be a vacuum leak downstream of the MAF sensor Possible cracked vacuum or PCV line/connection Faulty or stuck open PCV valve Failed or faulty oxygen sensor (bank 1, sensor 1)

*Sticking/plugged or failed fuel injector Low fuel pressure (possible plugged/dirty fuel filter!)

*Exhaust leak between engine and first oxygen sensor

 

Thanks for the reply.it has stock filter (no oil).also new fuel pump and filter installed less than 5000 miles ago.doesn't run any differently. I'm thinking oxygen sensor since it said "bank one, side one" also.how do you check if the sensor is bad? Thanks

 

It may be one of the Maps:

For the map sensor one is upstream and one is down stream. Good picture shows the sensors . 12140872679 and 12140872648

Bank one is one map upstream. Bank 2 is the other,

Diagrams

http://www.realoem.com/bmw/enUS/show...91#12140872679

http://www.realoem.com/bmw/enUS/show...diagId=11_3390



https://www.northamericanmotoring.co...sensor-is.html







https://www.northamericanmotoring.co...at-change.html

https://www.northamericanmotoring.co...0171-code.html

 

P0171 System Too Lean (Bank 1)

This individuals issue HERE was caused by a vacuum leak. You could smoke test the system to see if you can find a leak somewhere. Another individual HERE has the driver side intercooler boot pop off slightly. I've also seen some point to a bad sensor. I'd first check for leaks and then go from there as it is the cheapest alternative. Some more diagnostic info HERE, look at post #8.

 

I have a 2005 Mini Cooper S and have had the same problems with it all the sudden losing power try the mass air flow sensor that did not work change the fuel filter which seem to help some but it seems like it's happening more when I have the air conditioning on. It doesn't lose power and then gain power back you actually have to cut the car off and back on any suggestions? The check engine light will come on every time as well

 

Are you having the P0171 code come up or just engine problems?

I would start with finding a qualified tech to look at the car.