Hello,

FYI. 2001 Highlander V6, with 120000 miles.

Had DTC P0171 System too Lean (Bank 1),
and P0174 System too Lean (Bank 2).

I pulled the MAF sensor. It was filthy. I cleaned it with carb cleaner & after checking around for vaccum leaks, disconnected hoses ect., I reinstalled the MAF sensor, cleared the codes and after driving it for a couple of days the CEL has not come back on.

When ever you have a CEL on a Toyota it usually turns off the VSC and the Trac.
I had to do a zero point recalibration to get the VSC and Trac lights to go off & the system operational

Procedure is described here.

http://redirectingat.com/?id=252X400&url=http%3A//www.toyota-4runner.org/attachment.php%3Fpostid%3D223187 (http://redirectingat.com/?id=252X400&url=http%3A//www.toyota-4runner.org/attachment.php%3Fpostid%3D223187)

This is TSB BR005-03.


I found it on this post by newmanw10

http://www.automotiveforums.com/vbulletin/showthread.php?t=738062&page=2


Hope this can help someone. This forum is a great help to me!

Ventura HiWay