Hello,

I have 2009 xb, all stock. The check engine light came on about a year ago, got a code reader from Amazon and plugged it it. I am getting code P0101. When I looked it up it was a problem with the Mass Air Flow (MAF) sensor. I tried some cleaner, erased the code, but it came back after about an hour of drive time. So I bought a replacement, installed it, and erased the error code. But about a day later the code came back. I thought maybe I was sent a bad sensor. So I was sent a another new replacement and the same thing happened (both were OEM). So now I have a new sensor, have erased the code, but it keeps coming back. Any ideas what the problem could be, I'm starting to doubt it just the sensor itself.

Occasionally, I get sick of looking at the warning light and when I use the scanner to clear, it will display an additional code saying the engine is running to lean.

Any advice or thoughts would be helpful.

Thanks,

 

Have you checked the intake system for leaks? Maybe you'll get luck and see where something slipped off. Other than that, I don't know.

 

I'm with Superwht, I would look over the intake tubes to see if one of them has a crack in it or has come loose before the throttle body. Other than that maybe clean out the throttle body and see if that helps.

 

and actually take the intake system apart and feel around for the hole...some wear holes are sneaky and are only visible under load or when you twist the hose while examining it...in other words, don't just eyeball things, take the intake system apart and look for the leak...

 

Check your PVC valve, could be stuck open. That would also allow excess engine oil to contaminate your MAF sensor, the valve would cycle with intake opening/closing under normal conditions and limit oil deposits in intake.

 

Start car and spray around the engine with wd40, propane, brake clean or any flammable aerosol in small doses. Engine idle will rise when you get near the leak.