2006 XC90 CEL CVVT Solenoid code [Aftermarket bad part] Topic is solved

bfry · Post by **bfry** » 25 Mar 2018, 09:59

My ‘06 XC90 2.5T CEL came on around Thanksgiving. The car had ~140k on it - it’s been very well maintained, had all the recommended services and had minimal issues if any - it’s been a great car that we’ve used while raising our kids. I’m planning on giving it to my oldest who is now almost done with college.

Anyhow, the code was specific to the exhaust solenoid. It was the original solenoid, so I figured yeah, it’s prob time to be replaced so I replaced both the intake and exhaust solenoid myself.

Light was still on.

So I took it to a trusted machanic, who used to be a Volvo mechanic and has saved me a ton of money over the years. Anyhow, the code was still the exhaust solenoid and now the MAF. He grabbed a working MAF off another truck and put it on mine and same result - bad exhaust solenoid and MAF. He spent a lot of time on it and actually recommended I take it to a dealer cause he was stumped after spending a bunch of time on it.

The car was driving fine, no noticeable issues whatsoever so it was close to Christmas before I got it to the dealer. They spent almost a full day on it: verified solenoids were fine, MAF was fine, smoke tested it - fine and checked the breather box - fine.

Supposedly at the end of the day the car threw a code related to the cvvt camshaft hubs - so they recommended that if I replaced ‘em it would more than likely fix the problem and that if it didn’t the next step would be a pin-out test.

I called the mechanic, explained what was going on and he reminded me that that code for the hubs was not there when he had it, but that it was theoretically possible the hubs could be causing the CEL but pretty unlikely in his opinion.

Bottom line, I caved and spent the $1500 to have the hubs replaced. The CEL literally came back on when I was driving home from the dealer.

I eventually took the car back to the mechanic. He mentioned that someone else he’d been working with had been having the same exact issue and replacing the throttle body ended up resolving the CEL. He strongly cautioned me that it was a gamble and totally my call to try it. So I spent ~$900 and did it.

CEL is still on = exhaust solenoid. Mechanic is completely stumped.

Any ideas would be appreciated. Dealer is quoting ~$700 for the pin out and my guess is that they will just end up telling me I need a new computer...

Post by **oragex** » 25 Mar 2018, 10:54

Welcome. It is a good idea to ask on a forum. I would strongly advise, from similar experiences, that next time you are looking to replace a part, to buy a used one off Ebay.

The worst thing to do - and I think you've unfortunately learned it the hard way - is to listen to mechanics who are only 'guessing'. There are plenty of them around, including the main dealer.

By the way, speaking of the trusty mechanic, this is the first time I hear a bad throttle body could throw a CEL.

As for the problem, it is also good to inspect the wiring to the solenoids. A short may cause an issue somewhere.

Plus, these solenoids are extremely simple to test. Basically just unplug them, and connect two wires to it (you may also splice the wires to the connector just make sure to insulate them properly once finished). Then run a wire from the + pole at the alternator and a second one just touch a solid metal part on the engine: the solenoid should make a click. They are activated on/off by a 12V current.

There may or may not be a problem with the solenoid, but the CEL may come from a different issue. It may be a leak on the exhaust flexible or even a faulty Oxygen sensor (only suggestions, no need to replacing these parts). Were all codes pulled by the main dealer ? Weren't there other codes than the VV solenoids?

Post by **mrbrian200** » 25 Mar 2018, 12:46

Hmm. Here's a thought.
VVT solenoids and the evap purge valve share +12V battery power through a relay and fuse. Relay is labeled as the engine management relay, Fuse nearby. Runs through the 14 pin Grey connector visible in the fuse box.

Malfunctioning EVAP valve might also trigger the MAF code. Also a short to ground between any any of these three items and the ECU might pull the working voltage down on that circuit so that none of them work right, as might also if the evap valve were internally shorted any time the ECU operates the valve.
If the short to ground is between the evap valve and the ECU it would stay open all the time. If the short to ground was after one of the VVT solenoids to the ECU that VVT would likely sit the cam either fully advanced or fully retarded (I don't know which).

You could also have a bad connection on the supply side. I don't know if evap valve failure to open would trigger a MAF code. It might. The ECU likely expects to see a slightly higher flow through the MAF while the valve is open.

Key off all of these circuits after the relay should show 0 volts and no continuity to ground.

This is one of those 'if the vehicle were in my driveway I'd probably get it' examples. I don't have the diagram for the '06 XC90. Here's one for the '06 S60 2.5T. The diagram I do have for an '04 XC90 mirrors this design layout except for fuse and relay positions (FMA 2 vs FMA 3 etc, fuse position is different), but the functional design is the same. As such there might also be relay/fuse/wire color and position differences between the '06 XC90 and the S60.

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The dealer wants $700 for about 10-15 minutes to probe those wires? Oh my.
I understand they have a crap ton of overhead to cover, but isn't at some of it being covered by (profits? from) new car and parts counter sales?

Post by **SuperHerman** » 25 Mar 2018, 16:39

I have been through a similar situation with my old Saabaru. In the end, after the dealer told me my CEM was bad, which I replaced, I pulled out the actual shop manual and fault traced. My brand new O2 sensor was a counterfeit and once I put in a real one all was well.

Maybe the replacement parts are at fault.

Post by **ggleavitt** » 27 Mar 2018, 07:34

Seems like a good amount of effort has been put into this issue.

I'm wondering if maybe you can get all the codes posted, especially the Volvo centric codes from the dealer.

*edit for typo*

Post by **mrbrian200** » 27 Mar 2018, 09:23

Just to note: checking for problems with the cam solenoids and evap valve is just the place to start. If those are ok, it could be anything connected to the output of that relay causing trouble. As you have not indicated that it runs rough or has a miss, the injectors and coil packs are likely OK. This leaves the following items (and the wiring) as possible culprits: turbo control valve, PTC resistor, MAF, accelerator pedal position sensor, and possibly the ECU itself.

Post by **abscate** » 27 Mar 2018, 17:44

Harsh love.

If they didn’t put it into VIDA and read off the CVVT values, they aren’t Volvo mechanics. Move on and either get VIDA or find someone with it who knows how to use it. There is no reason to guess on a CVVT solenoid with that package.

bfry · Post by **bfry** » 29 Aug 2019, 19:51

Thank you to everyone for the responses and sorry for the huge lag in response time - I ended up getting the car fixed about 3-4 months later - same dealer - had some advanced tech guy come out and figure out what was wrong - according to them, one of the solenoids I had replaced myself was not Volvo genuine (true) and was causing a voltage disruption slightly outside of tolerances - they replaced it with a genuine part and all codes went away...at least this is what they told me and it was fine when I picked it up.

As my first boss used to tell me - truth is stranger than fiction!

Post by **SuperHerman** » 29 Aug 2019, 21:19

No surprise - look at my response above. I had the same issue with a counterfeit Subaru O2 sensor.

Mine was purchased on Ebay - where did you get your counterfeit part?

bfry · Post by **bfry** » 29 Aug 2019, 23:24

Yeah - that was a really good call by you - makes me wonder if dealer knew from the get go and just wanted to ring the register a bit...probably just being paranoid but nothing surprises me - lol.

I don’t 100% remember where I got ‘em from - I want say Tasco online? but I’d have to go back to that time period and check my cc charges to know for sure.