2013 XC90 catalyst code

[fireguywtc]

Hello all, first post!

My wife and I both have Volvos and my wife's 2013 XC90 has a problem and I am not sure what is causing it. The car has 97k miles and we have owned it since new. A couple of weeks ago, the car gave a check engine light which was P 0420 Bank 1 code. I know its a general code and I know what it usually means. However, the car is running good and I don't believe I have a catalytic converter or O2 sensor, and here's why.

I have a personal type scanner with Volvo software. After checking the code I had hoped that perhaps this issue was due to the car needing a tune-up. When we bought the car, it had the 50k miles service, but my wife didn't know if there was ever a tune-up done, so I changed the spark plugs and air filter. When I pulled all the plugs, the first five looked good, but the #6 plug had buildup and looked like it may have been running rich or misfiring.

These are the plugs I pulled out, unknown miles. The top plug is the #6 plug and is gunked up, the rest of the plugs were nice like the bottom one.


After I did the tune up, I reset the CEL, put seafoam in the gas tank and topped off the tank with 91 gas. After about a tank of gas later, the CEL came back on with the same code. To see if there was still a problem with the #6 cylinder, I pulled the sparkplugs from #5 and #6 cylinders. The #5 sparkplug looked good and the #6 plug already looked dirty and also was a bit wet with fuel.

Here is a picture with the #6 plug on the bottom this time.


After checking the plugs, I wanted to check possible causes of this. The first thing I checked was the coil with a continuity test. I checked and compared it to the #5 coil and it tested good. Next I checked the #6 injector for continuity and it also checked out good. I used the scanner to check fuel rail pressure and for misfires. Everything there looked fine. Finally, I used my scanner and checked the evap. system, and it failed. Not sure why though.

Again, the car is running good and I am not sure what is causing this #6 cylinder issue. Does anyone have any ideas or advice? I am in need of help and wanted to resolve this issue before I start throwing money at the catalytic converter. Thank you.

[thebull]

Hello Fireguywtc,
Here are my spark plug pics. They are 75 000miles and 6 years old. I don't think you have problem with the engine.

Cyl 1

Cyl 2

Cyl 3

Cyl 4

Cyl 5

Cyl 6


All of them


What kind of oil you have in there. Crank ventilation goes to #5 and #6 I think. Are you running synthetics? If you service your car to Volvo dealer it is possible that you have mineral if you did not request specifically for synthetics. Leak from the injector is very unusual at this point but possible. Simple fuel pressure check will tell.

Good luck
Regards

[fireguywtc]

Thanks for sharing. Your cylinder#6 plug looks way better than mine imo.The car has been getting standard oil. I wouldn't think it would cause only one plug to fowl more than the others, but I didn't know about the crankcase vent. I suppose I could look into that, but would it cause the P0420 code? That is my main goal, ruling out problems that might be causing this code to come up. I didn't want to spend around $1500 on a new catalytic converter if it wasn't the problem.

[thebull]

You are right. I should be more focused on this code, but could not resist the spark plugs pics
Do you have VIDA? You did mention you have some home tool. Anyway, this code must be triggered by the rear oxygen sensor. Bank 1 should be Cyl 1 to 3.
First check is the visual one. Check for exhaust leak. Black coloring or exhaust smell along the pipes. Check for damage as well. Even a pin hole could trigger the code.
Second is the rear oxygen sensor that monitors the converter efficiency. Sensor could be bad. Trace the wire and see if the connector OK. Unplug it, cleaned it, plug it.
Third will be catalytic converter bad. This is expensive and they do go bad, not because the engine is bad they just do. It is very, very strange on car like this but it does happen.

You could replace the coil on #6 cylinder and see what will change, but these coils they either work or not.
What I am curios is do you have any other codes? Are you doing small trips a lot like 4-6 miles?

[fireguywtc]

No other codes, this is the first ever for the car. Very rarely does it do short trips. My wife drives the heck out of this car which is why it has so many miles on it already. I will look into inspecting the exhaust soon. Here is the scan tool: http://www.ebay.com/itm/171942489065 not sure if it has vida or not but its made for Volvo.

One of the things that initially lead me to believe this catalyst code may be old spark plugs and needing to be tuned up was my S60. When I bought my car the prior owner had saved all the receipts and one receipt was a repair for a CEL for catalyst P0422. The work order stated it was for the catalytic converter and recommended trying a tune-up first as it could cause the code. The shop gave the car a tune-up, reset the CEL and it was good. Recently however, that code came back on the S60 (25k miles later) and I resolved the issue by replacing the rear O2 sensor. I assumed it was because of my cars age, it only had 110k miles.

Thanks for the help, I really appreciated it!