Error Code 25

[Sc400 Tuner]

I had my Check Engine Light come on lately, and I took the car to a freind with an OBDII reader. Well, he didnt have the proper connecto, but the engine light flashed the trouble code, once he plugged the tap into my car. It flashed two times, than five times, which I assume to be code 25. Does anyone have an idea what this code means?? I was told it was "air/fuel mixture error" the mechanic with the ODBII told me it was probably caused by the conical filter I replaced the oem airbox with. But I dont think that is it, If anyone else has had this problem how did you fix it? Or could my mechanic be right?(I dont doubt him, but I do question him :) )Thanks for the help.

[JPI]

It's your mass air flow sensor. This Mass air flow sensor measure the amount of air going through your engine. If it doesn't work then It would cause the lean condition. Your ECM coudln't determine how much air going through the engine. I would check the Mass Air flow sensor. Do you have an aftermarket intake? I've seen some lexus throwing this code after installing the aftermarket intake.

JPI