P0027 OBD code issue

[stevekaze]

Hoping to get some insight from the group on the current situation with my '07 XC70 w 2.5T. I have a P0027 code registering and here's what's been done: oil & filter change, exhaust valve and solenoid swap w/ new gasket, pigtail swap on both exhaust solenoid valve & VVT solenoid valve & new battery. After the pigtail swap, CEL went off long enough to have inspection and emissions pass. After inspection, ran about 25 miles & CEL came back on w/ same code. Back to my shop where they did some jump-wire testing on the harness that seemed to indicate harness was OK. Back to dealership for further investigation and they were trying to tell me that exhaust hub may have been over- torqued. I had the VVT & exhaust hub replaced about 18 months prior by my repairshop with a former Volvo tech on staff. At that point, I told the dealership to stop as I didn't want to continue to invest with them. The car runs strong with no engine hesitation or lag of any kind or no noticable dip in fuel economy and but if I can't figure out how to solve the CEL issue, I'll have to look for another car in about 20 months because it won't pass inspection. I trust that my shop did the hub replacement properly and I'm thinking since the pigtail swap temporarily fixed the CEL issue that this problem may be more electrical in nature.

Would really appreciate any suggestions from the group on what I should look into next. I've also since purchased an iCarsoft 2.0 Volvo specific scan tool and would appreciate any guidance on how it may help me pinpoint this issue from anyone familiar with that tool. Thanks in advance for the help

[Astro14]

You trust that the shop did the job correctly. I wouldn't.

The code is for the exhaust valve solenoid, right?

I don't think the pigtail solved it, the code was cleared, and the next time you hit the RPM where the cam timing should change, it didn't, so you got a CEL.

ICarsoft is like an adjustable wrench. Works, sort of, on all bolts. Not as good as a quality box end wrench. Not good enough for your need right now.

You need to put the car on VIDA and RUN THE STEPS to troubleshoot this.

Or pay someone with VIDA.

[Brett San Diego]

Agree with Astro14. This sounds like a job for an oscilloscope and most importantly someone who knows how to use it. The fault could ultimately lie in the ECU, new computer needed. But, you need a knowledgeable, scope-enabled technician.

Bare minimum, you'd want a bi-directional scan tool so you can manually command the ECU to change the exhaust valve timing and then observe if the valve timing has actually changed as commanded.

See this video:
https://www.youtube.com/watch?v=zp8lqx6KrR8

The iCarsoft VOL 3.0 for Volvo/Saab does say it has bi-directional capability, so you'll just have to surf through the menus and see if you can find where you can command the variable valve solenoids. This seems a relatively inexpensive system to have bi-directional capability, so maybe it's only a limited set of bi-directional functions. I don't know. Just hunt and click/tap through every menu you can find to see if variable valve stuff is available to you.

Brett

[stevekaze]

Yes, it is the Exhaust valve solenoid. Thanks for your suggestion. Forgot to mention in the original post that the Camshaft position sensor was also found faulty & replaced by my shop and timing was checked and verified 3 times and found to be spot on. Will try to find someone local with a VIDA to diagnose, but having trouble accepting that the dealership's thought that the exhaust hub was overtightened is the possible issue after the car ran fine for over 18 months after it was replaced.

[stevekaze]

Thank you for your thoughts as well. I had also heard that the ECU could be the issue, but am troubled by the fact that the dealership, who had this car for over a month, did not go either the routes you and Astro14 suggested. They seemed more content to keep stepping through 1 at a time continuing to run up the bill. Have had less than positive experiences with dealership services over the years, which is why I told them to stop. I, unfortunately have the Vol 2.0 which I don't believe has that bi-directional capability you mentioned.

[Brett San Diego]

Thank you for your thoughts as well. I had also heard that the ECU could be the issue, but am troubled by the fact that the dealership, who had this car for over a month, did not go either the routes you and Astro14 suggested. They seemed more content to keep stepping through 1 at a time continuing to run up the bill. Have had less than positive experiences with dealership services over the years, which is why I told them to stop. I, unfortunately have the Vol 2.0 which I don't believe has that bi-directional capability you mentioned.
It means that that dealership doesn't have a technician who knows how to use a scope or management won't allow a technician to take the time to do real diagnosis. Selling parts can be more lucrative, but they should have a guarantee that their work will fix it or no charge to you. You need to find a knowledgeable tech like Erik O. of the South Main Auto youtube channel that I linked to. That guy knows his way around diagnosis using an oscilloscope and the various aftermarket scan tools available.

Brett