View Full Version : CODE P0172

07-17-2011, 05:28 PM
Hi i have a 2001 celica gt. The car is put a code p0172. I change both o2 sensor and the car is still puting out the code. Does anyone know what else i can check and made change to get ride of this code. Oh yea i have a short ram air intake. And im running a 2 1/4" from behide the cat out to a flomaster. Thanks for all the help.

07-18-2011, 07:15 PM
Clean your MAF sensor.
Your intake may also be causing this, I'm not too up to speed on which intakes cause problems and which don't.

07-26-2011, 07:56 PM
Here's my suggestion...


07-26-2011, 08:34 PM
does the intake have a provision for the IAT sensor and did you use it?

07-27-2011, 05:22 AM
A simple question but since it wasn't mentioned, you did clear the code after replacing the O2's right?

07-27-2011, 05:44 AM
an O2 should not cause a 0172. Its extremely rare for an O2 to fail in such a way that it generates too much voltage, but that aside its the wrong code for an o2 failure. That code means you are genuinely rich.

That means you should focus on things that tell the system to richen the mix. IAT, MAF/MAP, coolant temp, fuel pressure, leaky injectors, etc.

07-27-2011, 05:52 AM
Just clean the MAF. And dont clean the little plastic goobie you see at the end, thats the thermister. The MAF gets its reading from the metal sensor up in the tube you cant see. So get yourself some non chlorniated brake cleaner and spray the fack out of in that tube (youll see what i mean mean you pull the MAF out). Then clear the code after you do that.

7th Gen Celicas have this issue, even more so when you put an intake on. Ill bet your MAF is just dirty. Its happened to me on my 7th gen GTS. Hell it happened before I even installed my CAI (I have an Injen).

07-27-2011, 02:48 PM
walmart brake parts cleaner is non clorinated. I use it. I have never thrown this code on both my early model 2000 gt-s though.

07-27-2011, 06:20 PM
Ive thrown it on mine twice. Once pre intake, one post intake. It happens.

08-14-2011, 07:14 AM
Followup to the OP. What have you done with this?