I have a 1996 Volvo 960 with a code of P0172. Check for vacuum leaks found some and repaired. Cleared codes drove 5 or 6 miles code came back. Does anyone have any ideas?

 

Have to keep looking for split or damaged elbows. If that doesn't work, you may have leaks at the manifold.

 

I had that code too when i first bought the car. you need to look closely at worn or broken vacuum lines near the throtlle area or yeah maybe it could be a leak in the manifold as RSPI said..

 

Hello-

I also have the same issue. No driveability problems, runs fine. Usually I would think that a vacuum leak would cause idle issues. Mine is steady at about 750rpm. Already cleaned MAF according to instructions on brickboard, but didn't help. Also have heard that there is an o-ring that seals the vacuum block on the lower part of the intake manifold. Sometimes that supposedly leaks. Seems random that that would be the issue, but I am going to try that as well. Read that it could be an intake manifold leak, but again- I would expect to notice run problems with any kind of vacuum leak, so I am a bit confused.

I have 120K on mine, and the O2 sensors have never been changed to my knowledge. I wonder if they could just be reading wrong? Is there a separate OBD code for a bad O2 sensor?

 

Hi 960 Rookie - did you ever figure out what caused your P0172? I have a 97 960 and am getting the P0172. I have cleaned the MAF, i have looked for vacuum leaks but haven't found any), and am wondering what to focus on next. I heard somewhere else about that o-ring on the vacuum tree mounted to the intake. Any ideas on what helped you?