Code PO 172? - Volvo Forums - Volvo Enthusiasts Forum

Go Back   Volvo Forums - Volvo Enthusiasts Forum > Volvo Vehicles > Volvo 850

LinkBack Thread Tools Search this Thread
Old 03-15-2011, 06:35 PM
Join Date: Mar 2008
Location: Granby, CT
Posts: 34
Default Code PO 172?

My son's 97 850 T5 (turbo) has shown a (generic) CEL code of PO172 which cross references to Volvo code EFI 231 or 232 (fuel trim). Any suggestions on where to start would be appreciated. (O2 sensors seem to be ok- my tool captures live data).

Many thanks
Reply With Quote
Old 03-15-2011, 11:03 PM
rspi's Avatar

Join Date: Mar 2009
Location: Albuquerque, NM
Posts: 15,674
Send a message via Yahoo to rspi

Every time I have had that code I have found a vacuum line loose from my PTC valve. It's part of the PCV system close to the turbo. Check the line to make sure it's connected and the elbow for a tear.

Item 10 closest to 8 on this pic.
'95 850 T-5R Wagon - Panther - Daily Driver 22 / 28 mpg
'98 S70 GLT - Lil' Red - Daughter 22/30 mpg
Volvo Repair Videos - Used Parts For Sale - Interior Lights For Sale - ABS Light? Click Here - Men's Mentoring
Volvo's of time past: '87 740 GLE, '79 262C Bertone, '78 264, '95 960, '97 960, '98 S90, '98 S70 GLT, '95 850 T-5R Yellow, '95 960, ,96 850 R...
Reply With Quote
Old 03-19-2011, 12:59 PM
Join Date: Mar 2008
Location: Granby, CT
Posts: 34

Thanks for the reply, esp. the link to the parts diagram. All the vac. lines and fittings have been replaced within the past year to avoid these types of issues. Checked the fitting you indicated (good, new) as well as all the other vac, hoses/fittings. Did find one hose that seemed a little loose, replaced that, cleared the code, and crossed my fingers. Within a day and approx. 100 miles it was back. Back to the drawing board. Again, thanks.
Reply With Quote
Old 03-19-2011, 01:12 PM
MattyXXL's Avatar
Senior Member

Join Date: Dec 2010
Location: Miami, FL
Posts: 1,267

172 is almost always a vac issue like rspi said...
did you check the elbows on the manifold and at the pressure regulator?

After a quick google search for some pics, I found this for reference....

Last edited by MattyXXL; 03-19-2011 at 01:15 PM. Reason: Added Link
Reply With Quote
Old 03-19-2011, 04:47 PM
Senior Member
Join Date: Oct 2010
Location: NY, NY
Posts: 1,218

Any driveability issues?

1998 V90, 162k miles.

1983 244 GL
1995 855T
Reply With Quote
Old 04-22-2011, 10:06 AM
Join Date: Mar 2008
Location: Granby, CT
Posts: 34

I know the original post is now a month old, but I want to thank Matty XXL for the tip. The elbow referenced in your link was completely shot. Replaced it, cleared the code, car passed emissions! Many thanks
Reply With Quote

Similar Threads
Thread Thread Starter Forum Replies Last Post
error code 172? cameyb Volvo 850 2 05-29-2011 04:41 PM
codes 172 & 505 bigcfromcinci Volvo V70 2 08-24-2009 01:50 PM
04.5 S40 2.4 CEL 172 99CivicSiBrian Volvo S40 0 01-27-2009 10:06 PM
P0090 Code??? Fuel Regulator (pressure code) badmonkey Volvo S60 & V60 9 07-28-2008 10:15 PM
how to chanslate the OBD II code to volvo code gzh Volvo 240, 740 & 940 1 03-21-2007 10:29 PM

172, 1996, 850, 95, 97, code, cross, obd, p0, po, po172, refrence, turbo, volvo, vovlo

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


All times are GMT -5. The time now is 12:58 AM.

This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. FordŽ is a registered trademark of the Ford Motor Company.