Subaru: new catalytic converter or new car?

I have a Subaru 2001 Outback with 100k miles, which I purchased about 1 yr ago from a private owner. I had the car inspected & the mechanic said it required a new “cross over pipe,” but otherwise was in good condition. The mechanic replaced the pipe with an after market part. Soon after the repair, the check engine light went on; when “read,” it said it was a problem with the “catalytic converter.” When I called the mechanic he explained it was just an issue of getting it “torqued.” I got a second & third opinion, both of which suggested getting the pipe replaced with a Subaru cross over pipe, as well as replacing the catalytic converter. They explained the after market pipe caused damage to the catalytic converter. I’ve already replaced the cross over pipe, but have hesitated on the catalytic converter because of the cost. I’d like to know should I a) get the catalytic converter replaced or 2) trade in my car, which kelly blue book says is worth $3,800, & buy a different car?


If the car is otherwise in good condition and seems to be proving reliable, you are then left with one question: can you get a better, more reliable car for the cost of having the catalytic converter replaced on this one? Unless this car is a rusted out, leaking, perpetually broken down hulk of a money pit, you are probably better off fixing this one. The only other reason to get rid of it over fixing it is if you have simply grown tired of this car and are looking for any reason to get rid of it. If that is the case, use this as a reason to get rid of it and get something you will like.

What If You Replace The Pipe And The Converter And Then The “Check Engine” Light Comes Back With The Same Fault Codes ?

That happens quite a bit. Catalytic converter codes often lead to unnecessary replacement of converters when the codes are set by something else, sometimes by a condition that is much cheaper to remedy. Those poor converters get blamed for everything, even by “mechanics” !

Some problems that set codes are faulty parts that identify themselves and other things are just symptoms of problems elsewhere, often things that set no identifying code of their own. I’ve seen an intermittent throttle position sensor or 02 sensor set no code of its own, but set a catalyst below effiency code.

Problems with things other than faulty parts set codes. Faulty circuits or dirty wiring connectors can. It could be the converter and I suppose it could be the pipe [?]. Depending on the code(s) it could be many many different things, even an exhaust leak.

Here’s what to do. Read from your Repair Orders (service receipts) and tell us the specific code(s). Post them here (PO123, PO404, P0420, etcetera).
Can’t find the codes ? Go to a “chain type” auto parts store (Advance, Auto Zone, others) and see if they’ll read the codes for you. Many do this for free.

Don’t give up, yet. Put the codes right here and we’ll take a shot at this and advise on the next recommendation.


The problem may be more with the people working on the car rather than the car itself.
Details on the problem might help to clear this up along with an explanation of what in the world the mechanic means by getting it “torqued”. That makes no sense at all.

First a 2001 Outback with 100k is worth far more than $3800 in New England(not sure of your locale) unless in rough shape. Shop around at exhaust shops.

I Was Being Too Polite By Not Questioning The “Mechanics” Who Have Worked On This Vehicle, But OK4450 Shares My Concerns. (Sometimes mechanics are relatives, friends, neighbors, or somebody trusted for years, and it gets kind of touchy.)

That is why my first post focused on going back to diagnosing the car’s problem(s), rather than concentrating on throwing on more expensive parts that may or may not do anything for it.

Lots and lots of mechanics are very good at repairing and replacing parts, but far fewer are good at proper diagnostics and fewer than that have the equipment and knowhow to get it done.

Let’s be sure it needs these parts, first.


Thanks for all the advice. So, the code that shows up when “read” is P0420. Any ideas/suggestions on what to do next?


Everything I read for it points at the cat. That doesn’t mean it is, though. Check all the connection, make sure eveyrthing’s tight.

If it does end up being the cat, be sure and get an original one. The aftermarket one’s may not be quite up to the task, and you may end up having to modify other parts to make it fit.

Someone else smarter than I may have anohter, better idea.

Good luck!

Reread My First Post. You’ll Notice That I Threw In A PO420 There. This Is Definitely One Of The Most Frequent Codes That Turn On A CEL And Also One Of Those That I Was Talking About.

I’d still bet you that replacing the converter would not eliminate this code for long. There are all kinds of things that can set this code. I’ve personally seen higher miles cars that use oil, clogged EGR systems, intermittent TPSs, etcetera, do it.

I’ve seen weather conditions and driving patterns exacerbate the conditions that cause it.

Tell a little about how the car is driven. Does it make a lot of short trips, never really getting up to operating temperature for a duration ?

Has the light been turned off a couple of times to see if and when it comes back and how long it takes or under what conditions ? Also, it’s possible that you’ll soon have another code or codes that will offer another clue.


Thanks for bringing this up, it’s exactly why I came to the site! I have a 96 outback with exactly the same issue. In fact, I had the converter replaced, twice. The engine light still coms on, and the code says the converter isn’t doing enough. So every year at inspection time (going on about the 6th time now) my mechanic resets the sensor, I drive it around, it passes the inspection, then a week later (usually while driving at interstate speed), voila, on comes the light. Is there a way of making the sensor a little less ‘hysterical’?


The Convertor is nearly at the end of the emmisions line beside the rear o2 sensor. Repeat failures mean something upstream is amiss causing the downstream to fail. Convertors typically last the life of the vehicle. Twice assures it, maybe a new mechanic…

I think the problem might very well be due to the crossover pipe. If there is any air getting into the exhaust system around this pipe, or anywhere in the exhaust before the second O2 sensor, it will trip this code.

I had a 96 Outback that had the same code. This code can mean your gas tank cap is leaking (yes really) or the O2 sensor (be sure to use OEM if you replace - these cars can be picky) or the cat. In my car, evaluation of the sensors showed that they were working correctly. I was resigned to getting a new cat. However, most of my driving was for short distances and my mechanic suggested that I try a longer trip. I drove an hour on the freeway at 65 mph and voila - the CEL went out. I think that in my case, I needed to let the cat get hot enough for long enough to burn off the stuff that may have been impairing the normal exchange that is supposed to happen on the surface. There are other reports of the same thing from Subie owners. I would recommend that you try it. You don’t have any modifications do you? If so, those can also result in an aberrant code.