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VVT issues, XC90 with a 2.5T, ECM-640A and 641A [ failed wiring] Topic is solved

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Khorn09
Posts: 10
Joined: Tue Mar 26, 2019 2:28 pm
Year and Model: 03 xc90
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Khorn09

VVT issues, XC90 with a 2.5T, ECM-640A and 641A [ failed wiring]

Post by Khorn09 » Mon Jul 22, 2019 3:47 pm

Hey guys!

So guys I got an XC90 with a 2.5T engine. some months ago. I posted on here a few different times and you guys have been pretty helpful. However I did figure out most of my problems on my own, I can't seem to figure this one out. So I'm coming to you guys and hopefully you can help me out, if not well at least thanks for trying.

Tell the problem right now that I'm having is I just had a check engine light come on. So I plugged in my Vida and it came back with both ecm-640a and 641a. After a search I found that it's related to the variable valve timing not being fast enough. Or something along those lines. So I checked the timing for the cams in the software. The intake seems to be fine, it follows the what the computer wants within about .03-1.5° at all times. The exhaust however starts out fine, within the same spec, but as the engine gets hot it gets really erratic. Like bouncing back and forth and doesn't stay steady anywhere. Like the engine wants 19° but it's at -5°??

I changed the exhaust vvt solenoid with a junkyard one, and it acted the same way. Initially fine, then all over the place. The truck seems to run fine. Also when I was revving to check the intake side cam timing it went as high as 50° when revved steady at 2500. That's what the computer wanted?? I don't know enough about this to be scared or not.
Last edited by matthew1 on Mon Jul 22, 2019 4:09 pm, edited 1 time in total.



Khorn09
Posts: 10
Joined: Tue Mar 26, 2019 2:28 pm
Year and Model: 03 xc90
Location: CA
Has thanked: 0
Been thanked: 0
United States of America
Khorn09

Re: VVT issues, XC90 with a 2.5T, ECM-640A and 641A  Topic is solved

Post by Khorn09 » Tue Jul 23, 2019 3:27 pm

Just an update guys, As of right now i think i figured out what it was. No CEL right now. and after a long time of running the vida cam timing app and verifying it. both cams stay within 0-1.2 degree variation now.

I opened up the cam covers, and verified the timing marks were still good; and they were. Checked TB tensioner; still looked good. check the cam sensors; swapped them, and they acted the same way. Tried unplugging the vvt solenoids while the truck was running and got no significant change. However, what I did find was the plastic tubing that covers the solenoid and coil wires was melted through. An exhaust solenoid wire had rubbed/melted through as well and was grounding out. So i just taped it back up, and am getting ready to grab some convoluted tubing to replace. Anyways, that seems to have done it. :shrug: hope this helps someone else! If I report back on this post, then you'll know that wasn't it!



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