MAF Vacuum hoses and p0172 and p0102 codes. Yay!

Post by **jblackburn** » 30 May 2012, 11:34

Only one there. The hose wraps around behind the intake manifold and comes out at the flame trap.

There are also several near the throttle body itself.

Any of them could be suspect, but usually a P0172 is caused by that one behind the PS pump.

larrya444 · Post by **larrya444** » 30 May 2012, 11:57

Replaced all the small ones. Could it be one of the bigger vacuum hoses? Or could it actually be the MAF?

Post by **jblackburn** » 30 May 2012, 12:52

You can have a shop smoke test the intake system to check for leaks before spending $200 on a mass airflow sensor you may very well not need.

I believe the P0102 is only showing up because the mass airflow sensor isn't reading in the expected values because of an air leak elsewhere. When you reset the computer, it's comparing to the default values stored in the computer vs. the values that it had learned over time with the leak.

Just a theory, anyway.

larrya444 · Post by **larrya444** » 30 May 2012, 15:19

I really appreciate it. Intake mani doesn't look too difficult and the part is pretty cheap. Might as well make sure everything is not leaking. Cleaning the MAF, too.

larrya444 · Post by **larrya444** » 30 May 2012, 16:08

Can someone tell me what that nub of the tube is there by the arrow?

: Is that my vacuum leak?; strange hose.png (209.98 KiB) Viewed 3599 times

Post by **erikv11** » 30 May 2012, 16:29

Pic is a little blurry but I am pretty sure that is the vent tube on the top of the transmission. Not related to vacuum.

larrya444 · Post by **larrya444** » 30 May 2012, 16:32

I'll quit yanking on it then.

Larry

Post by **matthew1** » 30 Jan 2013, 16:04

Here's another image of this port/line...

... and another topic with more photos and discussion about P0172.

gmullen · Post by **gmullen** » 11 Aug 2013, 10:02

Hi My 99' V70 T5 is throwing both of the codes in this thread. I checked the elbow under the PS pump and thermostat and it looks connected and in good shape. There is however another insulated hose and elbow right next to it that is disconnected and I cannot figure out what it is supposed to connect to. See the picture below and see the hose with the green clip. Can anyone tell me where this is supposed to connect?

Post by **erikv11** » 11 Aug 2013, 10:28

In your picture, the hose with the green clip is exactly the vacuum line that is the topic of this thread, the one everyone refers to as "the elbow behind the PS pump." That line connects to the PTC as discussed here, I would replace it with vacuum line as matthew1 describes.