Great detailed write up! Thanks for sharing that. Makes me want to turn a wrench again (at least more than an oil change haha)

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Hhhh you are welcome.. Hopefully this help someone to save $$$$. Believe it or not, someone here had their O2 sensor replaced and they charged Volvo warranty around $600 (labor only). Parts was $300. $900 total!!!

In my case, both sensors replacement did cost me only $260 ($130 per sensor). If I used Volvo branded sensors, that was going to cost me around $400.

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Appreciate such DIY stuff. Can you post/link it to the technical/DIY sub-forums? It is easier to find there and will be very useful in future.

 

Absolutely will do that ...

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Thank you for the detailed write up and photos! It is good to know this type of things. Shocked that at 55k miles they needed to be changed. From this article, it seems like O2 sensors should be part of the exhaust components 80k mile warranty in the US. Nonetheless, very useful write up!

The Federal Emissions Warranty is Often Overlooked When Your Vehicle Needs Emissions Fixes

Do you know about the Federal Emissions Warranty? Many people have never even heard of it and don't know that it can translate into free repairs for certain emission-related defects. Before you spend money you don't need to spend or go without repairs, check to see if your vehicle qualifies for...

www.ncconsumer.org

 

Yeah true but without a check engine light/permanent fault code, they won't replace them under warranty.

Anyway, I did replace both of them as preventive maintenance and to avoid further damage to the engine because of untrue reading from the dirty O2 sensor. Also, to make sure the car is running efficiently.

Honestly, if you notice the carbon build up on the Upstream sensor, that's definitely not healthy for the engine. I think the downstream one was still okay but I thought that no harm of replacing it as well.

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Is this the same as my 2017 xc90? I think I see the sensor but how do I get to it?

 

Is this the same as my 2017 xc90? I think I see the sensor but how do I get to it?

Same but you would need to remove the metal shield that's hiding the O2 sensor (driver side).

Reviving an old thread. I just did this fix after getting some intermittent odd too lean bank 1 codes for a while that finally evolved into O2 sensor circuit slow response bank 1.

I've never worked on this 2017 XC90 before but this write up helped me out quite a bit. Rock Auto had the sensor for about $130. It should be noted that I think the graphic is correct but the original post is not. The driver's side is the downstream sensor with the rectangular plug. The passenger's side (item 2 in the graphic) is the upstream sensor with the square plug. I ended up removing the driver's side (item 3 in the graphic) downstream one before I realized it was the wrong one, probably added an hour to my overall repair time. Just hoping to help anyone else attempting this.

Anyway, thanks for this post!

You are correct... I fixed the original post accordingly.


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Reviving an old thread. I just did this fix after getting some intermittent odd too lean bank 1 codes for a while that finally evolved into O2 sensor circuit slow response bank 1.

I've never worked on this 2017 XC90 before but this write up helped me out quite a bit. Rock Auto had the sensor for about $130. It should be noted that I think the graphic is correct but the original post is not. The driver's side is the downstream sensor with the rectangular plug. The passenger's side (item 2 in the graphic) is the upstream sensor with the square plug. I ended up removing the driver's side (item 3 in the graphic) downstream one before I realized it was the wrong one, probably added an hour to my overall repair time. Just hoping to help anyone else attempting this.

Anyway, thanks for this post!

 

I forgot to mention that after everything was put back together and I went for a drive, the only code I had was "Start/Stop service required." I'm guessing the smaller battery either needs to be recharged by a longer drive (I only went for 20 minutes) or perhaps this battery needs to be replaced. It had never shown up before. I did take the cover off and make sure the ground cable was tight at least but I'll take it for a longer drive tonight after work.

Thoughts?

 

That's totally fine. After max two days of driving, it should disappear. I experienced the same issue as well.

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So my code was gone but now has come back - my scan tool says:

Is the passenger side oxygen sensor the same thing as the "front heated oxygen sensor?"

 

The passanger side one is bank 1 (refer to the sensor 2 in the Volvo part diagram above).



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Thanks for the post. I wish I'd found this thread sooner. How long should this take a professional do you think? I have been charged 3 hrs labor and $313.95 for each sensor. I have an XC90 2017. Seems a bit steep to me.

 

That's too much...

Both O2 sensors are in the same area if you see the pictures. Once you open one, the second will require no more than few rotations.

It's straight forward but the space is a bit tight if you are using jack stands.

If you go with the Denso branded sensor, you will save more. When I checked the Denso branded sensor and the Original Volvo branded sensor, they were identical.


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Was my first time doing this on Volvo but didn’t take me 3 hrs, a Volvo mechanic/technician should be able to do both in an hour!
and this is like the socket I used:

also as I mentioned in earlier post the code did come back only once after replacing the sensor so it did fix my problem, just don’t know for how long as I traded my XC90 after a few weeks after but since it didn’t come back for me in a couple of weeks think it was good to,go…..

 

When I questioned them on the three hours, they simply said it was book time for those repairs: 1.5 hours for rear, and 1.5 hrs for the front. However, I suspect there is also book time for doing both front and rear at the same time, which would surely be less than 3 hours. Does anyone have access to the official Volvo documentation on this by any chance?

 

I think book hours still work that way: cumulative hours for each job. That’s the way it’s always been. Another good reason to have the VIP platinum warranty [emoji2369]


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Thanks for the input. Much appreciated.

 

Just wanted to add, I completed this on my XC90 T6 AWD. Volvo wanted over $900. I only replaced the downstream O2 sensor and after a few trips the CEL went away.

Couple of things I would add.

• I have pretty long arms but even I found it difficult to reach, you have to feel for it. The upstream sensor is easier.
• I only replaced the downstream sensor and it fixed it, but it's probably a good idea to do both.
• Start Stop was malfunctioning (giving an error) but this went away after two trips.
• The offset O2 sensor someone recommended above wouldn't fit for my downstream sensor so I had to find a fairly short 22mm wrench.
• Had to lever the plastic clip holding in the plug using quite a bit of force.
• Definitely doable with basic tools and very basic mechanical knowledge.

 

Thanks for all the info here. I felt confident enough to give it a go to get rid of a CEL and P0171 code. Got the car up on ramps, took the cover off, and stared at the upstream (passenger side) plug for 5 minutes wondering how my not-long or skinny arm was gonna get up there to reach it. It might be easier if it was up on a lift. Anyway, I took a break and changed my oil while the cover was off (after a Liquid Moly engine flush, in case that might help clear the code too), and spilled oil everywhere. I loved that long piece of cardboard I was laying on. Oh well. I'm going to give it another shot. One question I have is that the last step @Nerd23 stated was holding the reset button down for 5 seconds. What reset button would that be? Also, did you clear the code with an OBD or did it just clear up?

 

Which sensor are you replacing, or are you doing both? I did the downstream (driver side and harder to reach) which fixed it. I gave up on my first attempt. On the second attempt I basically just did it 90% by feel and it wasn't actually that bad, just make sure the exhaust is completely cold.

I think he's talking about the trip reset on the end of the left hand stock.

The code cleared for me after a while as my OBD reader wouldn't reset it (I think less than 48 hours). I've probably driven 3000 miles since and it's remained cleared.

 

How many miles on your car?

 

My p0171 code came back today, so it looks like the PVC didn't solve this for me (they replaced that under warranty). So now I'll go ahead and replace my O2 sensors. Thanks for the write up!

 

Reviving an oldie. Maybe @Tech can 100% confirm. I just pulled two from VDASH (bank 1, sensor 2). Forum says upstream passenger side, FCP says downstream... Volvo just says front.... I'll just do the two, but for the future. What side is what side?

 

Left (driver side) is downstream, right (passenger side) is upstream. I replaced my downstream (the one that looks more like a cylinder than a point) and it fixed my CEL. It's not too bad, just make sure the car is completely cold as you'll be hugging the exhaust.

 

Do you remember your code or what bank/sensor it pulled?

 

I don’t I’m afraid.

 

I'm having trouble figuring out the correct part numbers for my late 2016 XC90 T5 AWD

FCP Euro has 32253664 (32253664, 31380995) "Oxygen Sensor (Front). HEATED OXYGEN SENS"
and 32253665 (32253665, 31431005, 31422419, 31422419) "Oxygen Sensor (Front). HEATED OXYGEN SENS"
usparts.volvocars.com has this as well labeled "Variant code: CC01. front. "
and also has 32253666 "Variant code: CC02. front. CH 40932-. "
I put in my VIN and it also spit out 32253663 "Variant code: CC02. front. CH 40932-."

Since my chassis number is 067949 I guess I should use the CC02 variant?

Looking at Denso equivalents for my "XC90 II (256), T5 AWD, 183kW(249ps), B 4204 T23", There are two front sensor options:
DOX-0535 (Volvo 31293686 31319385 31319664 31370197 31370666 31422059 31422419 31431005 31480460)
and
DOX-0597 (Volvo 31439480 31439593 31439621 32253663 32253666 8890651502)

There is amazing variation in price on these from €87.12 to $324.62 but I don't want to buy the wrong thing.

 

Thanks for the write up @Nerd23 - I was ready to give up and take it to a shop to have them replace my upstream O2 sensor on my 2017 XC90 T6 R. Everyone in this thread wasn't lying when they said it's a tight squeeze, be prepared to come out with a few cuts and scratches after this job.

As an aside, I ordered the Walker Products O2 sensor, part 250-54043 and while it does fit, the wires are about 2-3 inches shorter than OEM. I managed to make it work, but just a word to the wise.

Thanks again for the write up!

 

I'm new here... and fairly new to Volvo's (little less than a year for our 2009 XC90) so still getting up to speed. I believe I have a bad sensor, keep getting a on-again / off-again CEL 420 and it doesn't seem to follow any particular pattern. Some have said it's a bad cat, but others have replaced and still it persists. I'm thinking I just replace all four sensors and see what happens. It's way cheaper than getting a new catalytic converter.
Thoughts anyone?

(Unrelated - my passenger side front door closer sounded broken until we noticed that bolt was lose. Tightened it up and no cracking sound!)

 

Kind of a bump, but I have a 2017 XC90 throwing a P0171 code on and off. I've never found the code active, but it seems to trigger on and off.

I know it's kind of a crapshoot between the usual suspects: upstream O2 sensor, PCV box, and Supercharger gaskets, so I'm trying to halfassedly diagnose & report back.

Using Torque Pro's logging/live data, I can see the upstream O2 basically reading 14.3 AFR basically constantly while the car demands other things.
On decel/coast, it will peg lean, but seems to taper toward lean over ~3 seconds or so.
On hard acceleration I can get it to go lower than 14.3, but it has to be pretty significant throttle. Read AFR is nowhere near the "commanded" value.
I also have significant positive STFTs (anywhere 0-"78%" but clearly that's not actually 78% trim) and LTFT (around 38 "%") I suspect there's a decimal place off in Torque or something.
This all said, I have zero info on what is "normal" for these cars AFR-wise, I just would expect more movement based on my only reference point of cars from 20 years earlier.
Torque also only reads at like 1Hz, so it's not the most useful thing.


I intended to smoke test the intake, but I haven't found the time, so I ordered the upstream O2 sensor and I'll go from there.

Will report back with results.

 

Kind of a bump, but I have a 2017 XC90 throwing a P0171 code on and off. I've never found the code active, but it seems to trigger on and off.

I know it's kind of a crapshoot between the usual suspects: upstream O2 sensor, PCV box, and Supercharger gaskets, so I'm trying to halfassedly diagnose & report back.

Using Torque Pro's logging/live data, I can see the upstream O2 basically reading 14.3 AFR basically constantly while the car demands other things.
On decel/coast, it will peg lean, but seems to taper toward lean over ~3 seconds or so.
On hard acceleration I can get it to go lower than 14.3, but it has to be pretty significant throttle. Read AFR is nowhere near the "commanded" value.
I also have significant positive STFTs (anywhere 0-"78%" but clearly that's not actually 78% trim) and LTFT (around 38 "%") I suspect there's a decimal place off in Torque or something.
This all said, I have zero info on what is "normal" for these cars AFR-wise, I just would expect more movement based on my only reference point of cars from 20 years earlier.
Torque also only reads at like 1Hz, so it's not the most useful thing.


I intended to smoke test the intake, but I haven't found the time, so I ordered the upstream O2 sensor and I'll go from there.

Will report back with results.

Having had to replace the upstream O2 sensor last year and the PCV diaphragm today, I would say just go ahead and do both. Neither is particularly hard to do and they’ll need done eventually. I used the Denso OES O2 sensor as it’s the same part as the Volvo one, and the IPD aftermarket diaphragm (which looks to be better quality than the flimsy crap Volvo put in).

Haven’t had to do the supercharger seal and praying it stays that way, but I think that’s less common. I have a 2018 XC90 T6 AWD with 63,000 miles.

 

Does anyone know how to reset the CEL after repairing the vehicle? My ANCEL 530 won’t reset the error codes.

 

I had a similar problem for years with an intermittent cute. Replacing the diaphragm didn't fix it, but replacing the PVC box did. Turns out the gasket was failing. Very cheap, very easy.

 

I’ll drive it tomorrow and see if the CEL goes away. The diaphragm was definitely torn and the noise went away so I think this must be it. If it doesn’t fix it I’ll replace the whole box.

Did you also replace the pipes? If so, how are were the pipes?