p0172 Code

charleskennedy23 · Post by **charleskennedy23** » 01 Feb 2016, 07:00

Hello MVS! My 98 v70 T5 (hagrid) has a P0172 code. I looked around the forum and it apears to me that this code is most often thrown by a problem with the vacuum hose that runs behind the intake manifold that is a part of the PCV system. Hagrid's PCV system was serviced about 14 months ago and all the visible hoses associated with that job appear to be good. Do you guys have any other ideas about what might through that code? I checked some of the vac hoses, and while they are original they do appear to be in good working order.

I am considering purchasing the vacuum hose elbow kit from ipd and replacing all the elbows to see if that resolves the issue. Do you all think this is a good investment?

Thank you for any advice

Post by **Ozark Lee** » 01 Feb 2016, 07:13

P0172 is almost always a vacuum leak somewhere and you have correctly identified the usual culprit. There are tons of places for a vacuum leak to occur though and any one of them can cause the problem. The elbow kit is worthwhile but I would replace all of the vacuum lines at the same time that you install them. Do them one at a time and it gets less confusing. I have had the caps on the vacuum tree get hard and fall off which will also cause the problem.

...Lee

charleskennedy23 · Post by **charleskennedy23** » 01 Feb 2016, 07:18

Thanks Lee... I'll start there...

charles

Post by **erikv11** » 01 Feb 2016, 13:24

I don't like to replace the elbows, I like to replace the whole line(s) with vacuum hose using either silicone or generic black rubber hose. Then I know the full path is intact and I don't have to revisit that particular vacuum line for a long time.

charleskennedy23 · Post by **charleskennedy23** » 01 Feb 2016, 14:05

Ok so I'm a little confused on exactly what I need to replace. I found a diagram on google that clearly shows the red, yellow, blue, and green lines. That diagram doesn't include the PCV lines (which have elbows) nor does it show any elbows. My car also has a small plastic purple line that goes from near the firewall to the front of the car. I also have a white line that goes from the front of the car through a check valve of some sort to the vacuum tree. Those small lines do have elbows on them. I just did the PCV system so I am going to rule those out as the culprit. After the PCV line which is the next most likely to be causing the code?

Post by **erikv11** » 01 Feb 2016, 15:24

The purple one is for SAS, the part from the SAS valve to the shroud is unlikely to be the culprit unless the solenoid and/or check valve beyond it is leaking too.

Other than that, any of them. I would first look at anything connected to the vacuum tree. Check the lines that connect the intake to the turbo snorkel pipe. The bottom line is those rubber and plastic parts are all about 18 years old, and live in a hot engine bay. I try to just replace them all when I get another P80 in the fleet.

Fair bit of vac line info can be found here: https://www.matthewsvolvosite.com/forums ... =1&t=65002

Post by **misha** » 01 Feb 2016, 18:06

Stuck open sas valve CAN cause running rich problem....so P0172 can appear because of it.When it fails it always do that in opened position.

Had it,removed it and plugged the port for sas valve and all related vacuum lines.

Post by **erikv11** » 01 Feb 2016, 20:27

Unfortunately, for this California car the OP can not just remove/disable SAS. Otherwise I would suggest it in a heartbeat, agreed.

charleskennedy23 · Post by **charleskennedy23** » 02 Feb 2016, 06:15

Thanks Erikv11! Sounds like replacing the vacuum lines per the post you referenced would be a good preventative maintenance item to perform whether that fixes the problem or not. Thank you for all the advice!

With regards to the SAS delete... Let's say an owner of one of these cars who lives in california performed the SAS delete, how would anyone know unless they pulled the computer and looked inside? Not saying I would ever do that because I am fully aware of the environmental damage something like that could do. I just want to to be prepared to discourage any friends from even considering such a vile act against humanity

Post by **erikv11** » 02 Feb 2016, 09:00

It's that pesky emissions sticker under the hood. As part of the CA inspection they will look at the sticker, and check that all the equipment is there. SAS valve, air pump, piping, all the crap that is so nice to get rid of. Anyway, I don't know that they check if the air pump comes on, and they aren't going to look for the diode (or know if the ECU is re-flashed), your buddy may be able to get away with it if he leaves everything in place. I have heard of people buying a new sticker, non-SAS ones do have a different part number sticker ...