what creates P0172, System too Rich (Bank 1) ?

I have been trying to track down the source of a P0172 code on my 96
850 with 108K, and have had all of the vacuum lines replaced with no
success. I am wondering exactly what creates this code...does it come
from both the upstream and downstream O2 sensors?

I have seen from previous posts that the mass air flow meter is a
common culprit for this. Is this more likely, or is it more likely
that the mechanic that replaced my vacuum lines missed the one that
was really bad?
Thanks,

Andy

 

Check the rubber vacuum "ell" at the end of the intake manifold,
in behind the steering pump area for being
broken. It is not easy to see and harder to replace.
Go to http://www.volvospeed.com/Repair/vacuum_lines.htm
for a picture of the vacuum line.
BD

 

In addition to vacuum leaks and the air mass meter, this code can be
caused by low fuel pressure (weak pump, regulator) or even an exhaust
leak between the engine and oxygen sensors.

It's also possible, but unlikely, the front oxygen sensor could cause
this code. (It usually causes different codes.)

--
Mike F.
Thornhill (near Toronto), Ont.

NOTE: new address!!
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

Thanks, guys. Indeed, I checked the vacuum hose behind the power
steering pump and it is bad. I'm posting another new thread, because
it does not look like I can replace this easily, and I don't know how
to move the power steering pump in order to gain access. Also, on
mine, it looks like a special hose which is thin going into the
manifold and thick going to the plastic pipe...??? Thanks again,

Andy

 

What you need is just the vacuum elbow your Volvo dealer parts department
will know what you need to perform you need a long needle nose pliers to
remove the elbow then very carefully & gently remove the elbow from the hard
plastic hose the new elbow just slides down no need to remove the power
steering pump whole job should take less then 1/2 hour

--
"*-344-*Never Forgotten"
Is for the New York City Firemen who lost their lives on September 11,2001.
The official count is 343, but there was also a volunteer who lost his life
aiding in the initial rescue efforts. And I will never forget them as long
as I live,
nor should any American.
"Mow Green"