Catalytic Converter???

[lewism2]

My 2010 legacy GT HAS 145,000 miles on it. It’s driving great but, the gas mileage is terrible and my dash is lit up like a flashing Christmas tree. The local mechanic said Cat needs replacing but wants me to come back to see if there’s more because of the flashing lights. I have days where no lights flash but it comes back. Any suggestions? Could it be sensors? If it is the Cat where should I get a new one besides the dealer

[whitetiger]

what lights flash? did your mechanic pull codes? if so, what were they? also a bad cat would only cause a CEL, which is only 1 light, not a lit up dash board with multiple lights you understand that you have given us next to nothing to give you advise on.

[Fabsx]

what lights flash? did your mechanic pull codes? if so, what were they? also a bad cat would only cause a CEL, which is only 1 light, not a lit up dash board with multiple lights you understand that you have given us next to nothing to give you advise on.

 

 

 

Actually if you get a cel, you’ll get cruise and traction control and brake light flashing.

So he is correct on the dash lighting up.

 

 

Sent from my iPhone using Tapatalk

[lewism2]

Brake engine and cruise light flashing. Traction control light on

[FLlegacy]

Brake engine and cruise light flashing. Traction control light on

 

Subarus do that when you have a check engine light on. I have surmised it is to make it impossible to ignore. My guess, and a guess it is given the info provided, would be the cat efficiency code. You can have it pulled at many local auto parts stores for free and that would point us in the correct direction.

 

Some helpful info you could provide:

 

Stock or tuned?

What mods have been done?

When did the issue begin?

Does cold weather affect it? Hot weather?

Where and what fuel do you use?

Has the timing belt been changed? Plugs?

Where are you located?

[dgoodhue]

The factory turbo catalytic converter is pretty pricy from Subaru (IIRC $1300, plus it is sort of pain to remove because of the studs often strip). I looked on rockauto and they don't sell a aftermarket replacement. So it OEM or a catted performance downpipe.

 

If possible, I would troubleshoot the problem by following the diagnostic tree in the service manual. You will need a scan tool (AP port will work as well) to do the troubleshooting. A wiring issue or new O2 sensor is a lot cheaper than a catalytic converter.

Edited January 22, 2020 by dgoodhue

[whitetiger]

the value of cats to scrappers has exploded in recent weeks. Ensure that your "mechanic" isn't trying to rip you off.

 

OP, you need to know why a Cat replacement is the correct repair. Dont blindly trust mechanics. Have him explain why that is the solution and not a sensor as mentioned above.

[lewism2]

Stock or tuned? STOCK

What mods have been done? None

When did the issue begin? A week or so ago

Does cold weather affect it? Hot weather? Not sure

Where and what fuel do you use? Shell Premium 93

Has the timing belt been changed? Plugs? Belt yes. Plugs were done once

Where are you located? Toronto

[GTEASER]

Go to your local auto parts store and pull the codes. We can only guess without a code.

[YeuEmMaiMai]

+1 for codes, +2 for data logging it.

 

I had P0430 and I data logged it.. found rear o2 sensor was going bonkers on passenger side, replaced both of them. Code has not come back since and that was over 1500 miles ago. code was coming back every few days before that. 2010 3.6R with 140K on it when I replaced sensors and now I am at 142K.

[lewism2]

Warmer weather here the past 2 days and coincidentally no lights lit up on the dash. Gas mileage still sucks

[YeuEmMaiMai]

^ get basic OBDII dongle for $10 and then data log it. You need to see what the CEL is for and what the car's sensors are doing.