Have you read this thread? One thing in it mentions the PCV as well.

3.2: P0420 & P0430 Unofficial Guide + Oil Consumption

Thought this might be a good time to address the P0420 & P0430 codes found in the 3.2 as many of the 3.2s are in the 150k mile range or approaching 200k miles. Some SwedeSpeed members are good at reading the threads and finding solutions while others have trouble understanding the information...

www.swedespeed.com

 

Thanks for the link, I had not checked the thread. The oil has been changed every 5k miles or so and on the last change I emptied right around 7 quarts, so if there was consumption it would be minimal. The PCV does not seem to "whistling" to me. I did the checking like volvosweden does in his video and I don't have the excessive suction (

) or the air escaping (

). Do the values I recorded point to a clogged cat?

 

I don’t know your specific situation, but if you were getting a zero value for the fuel trims with the primary O2 sensor, that’s a good start for a change. But I would have screen captured more than one time different times and mileage.

The PCV doesn’t need to be whistling to be bad. I just changed a diaphragm on a 2013 T5 with 140k miles and while it improved, it didn’t fix 100% of the PCV issue. The owner, my neighbor, bought only the diaphragm against my recommendations. He is now ordering the whole unit. Get an entire PCV and the recommended maintenance is by mileage even if you don’t hear a whistling. If you have more than 100k miles or are close, it’s time. I am assuming you read the first couple of pages of the stickied 3.2 thread as explained also in the Unofficial P0420 thread. The PCV is mentioned to change by mileage, so are many other items.

Then there’s checking all the intake parts for any leaks. The Unofficial P0420 thread has a link of how to check the primary and secondary O2 sensors. Both banks (all 4 sensors) should be mapped at the same time so you can compare each bank. It’s in the YouTube video link in the thread.

The mileage driving on the new O2 sensor doesn’t matter as that code sometimes needs to go through start/stop cycles. When installing fresh O2 sensors (which should be replaced in pairs) the ECM should be cleared as old trims are stored. It takes some time for these to be updated well, including by mileage and start/stops. A code could be thrown in that adjustment time.

Also, not knowing your climate, catalytic converters are less efficient in colder weather. It’s one of those things like batteries. They usually die in July, but you don’t realize it until December. The cat or the engine condition may show itself in colder months and hide in hot months if it’s just over the inefficient threshold.

For these reasons, this is why we go back to the checklist in the Unofficial P0420 guide and the maintenance recommendations in the stickied 3.2 thread.

 

I appreciate all the guidance. I will take a closer look at checking the O2 sensors. When you mentioned that the ECM should be cleared when O2 sensors are replaced, is that a process you complete in VIDA? I've seen a reference in the threads to "Vehicle Communication>ECM>Advanced>Reset Adaptations" and wanted to check that's what you are referring to.

As for climate, we're in New Mexico. It's dryer than most of the country and the temperatures have been dropping but I can't say that has changed the frequency or mileage when the CEL appears.

PS: I will order a PCV Valve Cover, the process seems pretty straight forward.

 

Well, you’ve driven enough now so no need to reset the ECM.

What’s your mileage on the XC90?

 

118k, changed the O2 sensor about 1k miles ago.

 

Have you checked for exhaust leaks? Having a leak between the upstream and downstream sensors can cause efficiency codes to be thrown.

 

I've done a visual check but will look again more carefully.

 

Go to Volvo tech Tip site, create a profile and you can download all of the past issues. They all have very helpful information on older Volvo's. I added some here.
Volvo TechTips Issues Archives - Automotive Tech Info

The MIL Codes and faults PDF talks about CAT codes.
The 6 cylinder engine from 2007 to 2014 can get cat codes. I have had customers use CataClean, pour into gas tank, and the Cat code did not return for some and no help for others. Search YouTube for 02 sensor codes/spacers ect. There is a spacer that you install in the rear 02 sensor that would keep the code from returning. AutoZone part # 42009. I used this in my 2000 Subaru Outback years ago. The only time it would code is if it was raining a lot and you drive thru a rain puddle that splashed up and cooled down the car. Erase the code and good till the next rain event. Normal raining it would not code.

 

Here is the Cat one, Summer 2022.

 

Thank you! I have lots of reading to do over the next few days. I really appreciate all the help and resources.

 

Any owner doing maintenance work and NOT grabbing these TechTips and keeping them around for future reference is doing themselves a disservice. Behind VIDA and the EWD, this is the best experiential resource that one can find for our vehicles. Every time I see one of these, I grab them and keep them around as somewhere along the line what's in these documents will directly address most of the issues you'll have on your vehicle. Really worth the time and effort to review them all.

 

Another alternative to CATCLEAN. It has worked for a few MVS members including Robert DIY if memory serve me right. Try a few simple things first. Scotty provides a nice simple explaination of P0420.
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Hell no!!! Not for 3.2!!!! Do you even know how difficult it is to take these cats out? Do you have any experience with the 3.2? And Scotty Kilmer? Lol

The generic tech tips are nice and it seems like you have VIDA which can give more specific info with the codes. You can get generic tech tips from YouTube and Google, maximize your search.

The more specific 3.2 maintenance and trouble points outlined in the Unoffical P0420 thread linked earlier in this thread. The stickied 3.2 thread also goes over many many of the important points. With almost all 3.2 XC90s in the high mileage, we’ve all learned more specific things to look at.

I am approaching 168k miles with never having a P0420 code and know of others never having a code. I drive the piss out of my XC90 too. The 3.2 can drive well for a long time so people don’t do the maintenance. Unlike a 2.5T where you are expected to change the timing belt/water pump, the PCV, and the ignition components all around 100k miles. And god forbid if you have to do the alternator, the intake manifold gaskets, etc in a V8.

Like mentioned before and in the 3.2 Unofficial P0420 thread, the maintenance and upkeep are the biggest issues. Always best to start with that checklist before jumping into conclusions and spending large amounts of money on parts or diagnoses from shops.

Good luck!

 

Seems like this is a reasonably common issue for the 3.2 motor. Never come across one of these errors in my V8s and I replaced both sensors outright on my 5 cylinder when one of them coded but I never had a cat or sensor problem otherwise. There's the larger thread on the event(s) in the forum which has lots of possible reasons and there are numerous side threads on the overall subject but has there ever been a general consensus as to a singular general root cause or a prime cause specific to the I6?

 

This is a pretty common problem on every Volvo that uses this or the turbo version of this motor, so S80, V70, XC70, XC90, usually when they get to around 110-130k miles. I battled it for a time with my previous XC70. I've never seen a single root cause for the code - folks have replaced cats, repaired broken flex pipes, replaced O2 sensors, done hard resets, replaced plugs, PCV, etc.

Aside from obvious mechanical damage like a broken flex pipe, though I have no proof I place some of the blame on Volvo's typical conservative engineering, setting codes for every little thing, or just bad engineering that even if you do everything right the cats don't last, which just shouldn't happen on a car with 110k miles.

 

Btw, the specific Catalytic Tech Tip that @volvogod attached goes over the exact same thing: don’t rush to think it’s a catalytic problem, do the maintenance, check diagnostics like using Vida, etc.

Just reinforces the sticky 3.2 thread and the Unofficial P0420 thread. Go through your checklist, don’t rush to judgement, and re-evaluate when your engine is up to date.

One thing those tips won’t mention, but is mentioned in the sticky 3.2 thread and I’ve mentioned to several others is you didn’t mention your fuel system. Besides the fuel filter, add a tank of good fuel system cleaner. Ensure those fuel injectors are spraying well. Seafoam isn’t the best, so use a modem one.

Again, get that maintenance list checked off first.

 

Thanks again, I'll add a good fuel system cleaner to the list, any recommendations? I changed the fuel filter when I did the spark plugs and air filter in the summer. In terms of gas it's been 91 octane, either at Costco or Chevron and I've used Techron a couple time in the past 3k miles.

 

I personally use Liqui Moly’s fuel cleaner, but you can get good ones at Walmart.

Now that you mention Costco, in several vehicles, I had issues with Costco gas. My OBDII dongle showed the timing was being pulled for their premium gas versus Shell. I stopped using Costco gas for that reason. They say top tier for detergent, but unsure about the overall quality. There has to be some corner cutting to make the gas cheaper.

Another question. Have you owned this XC90 since new or did you acquire it used? Do you know its maintenance history?

 

I got it used, with some of the maintenance records. These are mostly oil changes (regularly around 5k miles), brakes and tires all at Volvo dealerships in SoCal and AZ.

 

So reporting back in on this issue. Before heading out to Soutern California I replaced the following:

Volvo PCV Valve Cover Oil Separator - OE Supplier 31319642 - FCP Euro
Fuel Pressure Sensor Bosch 0261230238 - Amazon

I also cleaned the MAF and used one bottle of Liqui Moly PRO-LINE Fuel System Cleaner 500ml Can LM2030.

No CEL during 2k+ miles. A couple of environmental factors which I don't know if or to what extent could have had an impact. Temperatures were warmer, so mid 40s to mid 60s and the vehicle was at sea level.

 

That's great news! Looks like a lot of little factors which all contributed to the CAT getting slightly dirty has been cleared or cleaned up. Change the oil every 5K miles or twice a year. Use Premium fuel and add a fuel injector cleaner from time to time. If all that can't keep the CAT clean in the future use the Lacquer Thinner per Scotty. Merry Christmas and a Happy New Year.

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Great update!

It goes to show it isn't a part that the 3.2 needs, but maintenance. Don't assume all 3.2s have a design flaw and don't assume you will need new cats. Start with the (right) maintenance and get another baseline.

Shame on Volvo for recommending 7k mile oil changes (should be 5k or less), using conventional oil (should be synthetic), and saying parts should be replaced at 150k miles when they should be replaced at 100k miles.

Enjoy your code free 3.2 and Merry Christmas!

 

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What you suggest is dangerous because you are assuming that the catalytics’ precious metals are still good and the only reason for the P0420 code is a dirty cat.

After all of the laborious work to remove the primary cats/manifolds, suggesting to clean them out with thinner instead of replacing is bad advice. Imagine having to do the work twice and still needing to buy new cats.

Do you have a 3.2? Btw, Scotty is wrong about all Toyotas and the clear example of Toyotas suffering oil consumption due to piston rings is an example.

 

Had the OP known about the Lacquer Thinner he probably would have tried it first. As for the CAT removal and cleaning we already agreed that it would be a last ditch. Even then I stated to the OP that he should decide for himself whether to do a certain work depending on his skills and likes and not let others like yourself or I talk him into or out of work he deems reasonable.

Someone can swap transmissions all day but won't pull a door panel or look into anything electrical.

As for the assumption the CAT is still good. Everything that was thrown at it did not work to remove the code because they were not the cause. As most everyone here would agree, nothing stood out causing the code. Everything however brought the car back towards Stage O as much as possible. With the cleaning of the MAF, Liqui-Moly and 2K miles of driving it's back to normal. If the CAT was bad the code would not have gone away. Correct assumption since it only takes a few percentage of inefficiency for the CAT to throw a code.

I looked at the bigger picture to make an assumption while ruling nothing not. If I assume I know everything then I have nothing to learn nor can I learn.
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Lots of assumptions without experience from you. Again, do you have a 3.2 or ever worked on one? Have you ever worked on the XC90, with its height and trying to reach back at the exhaust manifolds?

The 3.2 exhaust manifolds/primary cats are a bear to remove. Access is very difficult (above & below), rust is normal, breaking pieces is normal. It’s one of those jobs that hurt the body and scrapes arms.

You are making the wrong assumption here that it’s easier to remove and install the 3.2 exhaust manifolds/cats than to bring the maintenance up to date. That’s just plain false and it clearly shows you don’t understand the 3.2 in the XC90. Insinuating what others would do is also a poor assumption.

We are talking high mileage XC90s. This isn’t an 80k mile issue. It’s happening between 125k-180k miles or more, depending on maintenance history. The precious metals could be safely assumed that they are worn out. We aren’t talking a 90s 5cyl here, this is an Ultra Low Emissions Vehicle (ULEV), one of the reasons it replaced the aging 2.5t. That alone would mean the emissions threshold is tighter. If the trouble to remove the exhaust manifolds/cats is done, replacing them is the sound advice.

It’s clear you don’t understand the 3.2 and are feeding general advice based on Scotty…Not on the 3.2 specifically, members’ experiences, nor the XC90 platform.

 

Since the code is gone for now we can at this time assume the CAT was not bad. As for the removal for cleaning please reread the previous post carefully and try not to talk the OP out of trying to clean it if he wants to do so. I wouldn't discount your overall experience on a matter if you looked at the entire picture and made an assumptions on repairs for a different make.
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We can also safely say you have never worked on a 3.2 since you avoid answering that.

I have a larger/full picture since I know the 3.2 very well from my own ownership experience, that means I’m considering more 3.2 specific factors than Scotty (dare I say you too). Scotty removed a cat in his video and cleans it.

Cataclean is mentioned in the Unofficial P0420/P0430 and oil consumption thread, which could bring a preview if lacquer thinner could work since it’s working off the same principle.

3.2 owners should Google the paint thinner recommendation from @CASwede. Here are some results,

Does paint thinner really work on cats | EricTheCarGuy

Im concerned that it might damage the engine or make it stall.

www.ericthecarguy.com

Video of actually trying to add lacquer thinner to the gas, no cat removal and clean, did not work in the end. From a real mechanic.

Another lacquer thinner fail video

 

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You know as well as I do from other posts I do not own nor have I worked on a 3.2. From what you are saying about the difficulties and what I've read it's the last motor I want to have in the fleet. Thank you for sharing your frustrations with it.

Are you also saying since none of parts or work done by the OP fix the problem he should have not tried it, like the Lacquer Thinner. Of course it won't work for a lot of people with bad CATS. It'll only work when it starts to miss the threshold and throw a code as I have repeated how many times and per Scotty . I'm sure you've seen lots of those videos where the LT worked so I won't need to post them.

Not sure why you insist on people not trying the LT when there is a P0420. Eric the Car Guy and a bunch of others tries it knowing nothing is dangerous as you say and for many its worked.

(EDIT Don't be offended or upset as I don't have much more to add so won't further reply. Have a great and blessed New Year!
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