[cardoc]

Is this a ULEV 2.5 or a 3.0?

Either way, LTFT is too high. The ECM is adding fuel which indicates a lean condition. The Calc Load is also up a bit. Where do you buy your gasoline? High alcohol content requires a higher volume of fuel shot.

How long was the engine running when this was taken? Temp is a little low.

If you haven't perused them yet, here are a couple threads of interest:

http://www.subaruoutback.org/forums/66-problems-maintenance/49537-p0420-diag.html

http://www.subaruoutback.org/forums...spective-p0420-catalytic-efficiency-code.html

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[dralb]

Is this a ULEV 2.5 or a 3.0?

Either way, LTFT is too high. The ECM is adding fuel which indicates a lean condition. The Calc Load is also up a bit. Where do you buy your gasoline? High alcohol content requires a higher volume of fuel shot.

How long was the engine running when this was taken? Temp is a little low.

If you haven't perused them yet, here are a couple threads of interest:

http://www.subaruoutback.org/forums/66-problems-maintenance/49537-p0420-diag.html

http://www.subaruoutback.org/forums...spective-p0420-catalytic-efficiency-code.html

.

This is a 3.0. I just picked up the car and it has 1/4 tank, so I stopped at a Mobil and topped of with midgrade. The station was right off the highway near a restaurant/hotel complex, so I assume they have decent turn over.

The car was warmed up a bit and then driven 5-6 miles through town and then onto the highway. This was right after I got onto the highway. The temp may be a bit low as it was 30F outside.

Last night I cleaned the PCV which was gummed up and the sir filter needs a change. I am planning to swap that and do plugs tonight. I have no idea if or when they've ever been done. I just got the car and haven't made it through the first tank of fuel and I believe it had been sitting due to the rust on the rotors and the avg. mpg showing 4.5mpg. It was from a car lot, so I am betting it had been doing nothing but short test drives and running in place quite a bit.

I read through your post and watched the video. It was very helpful. I wish I had a scan tool that took reading actively, it would help. I didn't see any vacuum leaks, but I suppose the gummy PCV could cause a lean condition if it was not closing all the way. I had ruled out the t-stat as the car gets to temp and stays at 1/2 needle with good heat etc. I am planning to flush the cooling system as soon as I have a chance.

Any idea how long it will take to reset the OBDII data? I need to get an inspection and if the codes were recently cleared, it's a no go. I am assuming a couple hundred miles of varied driving would do it.\\

Thanks for the reply. I am hoping it is just a case of the simple things and some maintenance will take care of it.

edit: I had driven about 200-250 miles from the time I picked it up before the light came on. I am assuming the dealer reset it at some point prior to putting it up for sale. The oil was recently changed and looks clean, but I am probably going to do that too just so I know what's in it for weight etc.

also, fwiw, the fuel around here is listed at up to 10% ethanol.

 

[cardoc]

Clean the MAF sensor with appropriate cleaner, clean the throttle body, use highest octane available. The temperature should be closer to 190-205 regardless of outside temperature, so you may need a thermostat.

Does the tool you used for the data have the ability to erase codes? If not, the light will go out on its own once the ECM sees that the issue is not there in 30-70 miles of driving. That is unless the CAT is deteriorating, but I can't determine that without an active data stream. Otherwise, go to a parts store like Advance and use their scan tool to clear it.

 

[dralb]

Clean the MAF sensor with appropriate cleaner, clean the throttle body, use highest octane available. The temperature should be closer to 190-205 regardless of outside temperature, so you may need a thermostat.

Does the tool you used for the data have the ability to erase codes? If not, the light will go out on its own once the ECM sees that the issue is not there in 30-70 miles of driving. That is unless the CAT is deteriorating, but I can't determine that without an active data stream. Otherwise, go to a parts store like Advance and use their scan tool to clear it.

I erased the code last night. I just got back form topping off the tank with premium. The last MAF I cleaned was on my 1988 535is, lol. I'll look into it. After I do the cleaning and swap the plugs, I'm planning to do some road trips and see what happens.

If it comes back on, I guess I'll swap the t-stat and rear O2 and reset it again. If I lived closer, I'd just bring it there, lol. I just don't trust any of the local shops.

Can I use that freeware software and get a patch cable for my laptop and use it to get active data from the car as I'm driving it?

 

[dralb]

Swapped plugs tonight and cleaned the MAF sensor. Have driven about 80 miles of mixed conditions so far and all is good. Tires, rear suspension and a sticker Monday and I should be gtg!