2001 S40 three way catalytic converter
 

Just got the check engine light. Brought it to dealer, and the man told me that the code was for the 3 way catalytic converter. I know they had it up on the lift, I saw it. But the $1,500 price tag doesn't taste good. I just checked auto stores, and it seems the converter averages about $200-$300 bucks. Maybe I could buy the part online, and bring it to my friend who has a muffler and brake shop?

What was the code they pulled? And did they tell you what CAT was bad? IIRC your car has 2 of them.

I'd just take it to your buddy with the shop and have him double check the dealer and if need be he should be able to take care of it for you.
The dealer should of given you a quote with the part number on it. If you want to stay OEM Look up the part on tascaparts.com

Buy this, place it between the bottom O2 sensor and the cat convertor. It has been working for me for months now.
Oxygen Sensor Spacer (CEL Boss)

An O2 spacer is a way to go if you have O2 sensor issues related to a high performance cat thats throws below efficiency codes or no cat at all.
It won't do you any good if you have a failing cat. It can restrict airflow and be the cause of other issues.
Besides here in the US having a working emissions control system is a federal regulation. I don't know about where you are Florida, but there's county's that have annual emission inspections to be able to register you car.

By failing cat you mean one that is falling apart internally? I have personally had 2 cat failures. Both failures gave a rattling sound from the internal honeycomb structure falling apart. However, specific to my 2001 S40, there was only the check engine light for "cat efficiency below limits". $1 says the dealer simply pulled the code and suggested the very expensive repair. I'm suggesting this simple fix as an alternative. As always, my advice is worth the price you pay for it... :)

Correct. That's why I said he should have his friend that owns a muffler shop double check what the dealer is saying. I'd assume his friend would hook him up with a free inspection.

I would not take your bet cause chances you're right. Lol.

If you're getting a "cat below efficacy" code and you cat is still properly functioning then your problem is more then likely a failing O2 sensor. The spacer will work there to pull the O2 sensor out of the exhaust stream and trick the sensor, but your sensor is still bad and should be replaced. The whole point of a spacer is to trick O2 sensors readings and not triggering a CEL.

Case in point is both my 850R and my S60R. I'm running CATless in the 850R and before I got it tuned specifically with a rear O2 delete I ran a spacer to eliminate the CEL with the CAT below efficacy code. And my S60R I have a high flow CAT that doesn't work as well as an OEM CAT until it's warmed up so I would occasionally get the CAT below efficacy code. The spacer fixed that as well.

Either way, I still think you should find out exactly what is causing the CEL (by way of your buddy) and take the proper action to fix the car.

Cats just about NEVER EVER go out on these cars. With the exception of engines that burn oil (greater then 1 qt per 1000 miles)

I would bet you it is a broken PCV hose, clogging PCV system, or clogged PCV valve.

I'll bring it to my friends shop after work tomorrow. I saw the dealer mechanic put it on the lift and then ( in the front ) point to the service rep both on the left side and right side of under engine. I don't know what the code is, but paper work has these numbers..817POLS, STK:V1644, DLR:7214, ENGB4204T3, 1) R/C:5415, 3) F
Thanks for your feedback!

Would a fowled up PCV set off the same CEL that would indicate a bad CAT? I'm just curious for future sake.

Good call. Let us know what you friend says.

Started car last night to wash it, and CEL was OFF. But that didn't last too long because on my way to work this morning after about 7 miles, CEL came back on. Alright, my friend expects me this afternoon.

Just called dealer. He told me code was ECM5A

Ok, my friend at the muffler shop says it reads "cat below efficiency". He put it up on the lift, but didn't knock on the cat or anything. And yes there are 2 cats. So he plugged in the reader and read what was going on in the engine. The temperature going in to bank one seems fine, but no reading on temp coming out? He thinks maybe it's the oxygen sensor. Cleared CEL, told me to come back Sat. morn. if it comes back.

There you have it. https://volvoforums.com/forum/images/icons/icon14.gif

Ok, should I replace this sensor? Which one might it be? Aren't there 2 different O2 sensors?

If it truly is the sensor, I would replace it just to keep the CEL from coming on. Do you have to deal with the yearly emission inspections there in Florida?
In this case it's the rear O2 sensor that's after the CAT.
But the rear O2 sensor has no bearing on the drive-ability or performance of your car. All it there for is to monitor the effectiveness of the CATs to ensure your your emissions are where there suppose to be.

Got some more info from my friend with the garage. He called to ask me if the CEL came back on. I said no, should I replace the sensor, he said no. In fact he said cat looked clean underneath and axle was probably fine too. No leaks, nothing broke. He said "don't fix it if it ain't broke'.
By the way Matt, here in Pinellas county we don't have emissions regulated. This is becoming a good hobby learning about this car, and enjoying the ride. I drive 60 miles a day round trip to Tampa for my job!

The top O2 sensor is used for feedback to the car's computer for adjusting the amount of fuel fed to the engine (aka fuel trims - long term and short term). The bottom O2 as Mad Matt wrote is to make sure the cat convertor is performing properly. However, if the bottom O2 is bad then you get the same code as if the cat was bad. That's why I suggested the O2 extender. It moves the O2 sensor out of the exhaust stream and stops the trouble code from being set to begin with. Odds are if the trouble code was set once, it will reoccur. It's just a matter of time.

The bottom (downstream) and top (upstream) O2 sensors are different only in the electrical connectors to the car. If you purchase one I highly recommend the Volvo S40 specific version rather than the generic. The specific version will have the proper connector already mounted. The generic O2 sensor involves cutting/splicing to the old connector.

Buy Bosch Premium Oxygen Sensor 16292 at Advance Auto Parts

Thanks Hudini!

I got a new sensor in the mail as well as a new catalytic converter. I just cleared the "below efficiency, bank 1" code for the 3rd time in 3 weeks.. My replacement cat is a Bosal 099-19801112. I know this is not oem, but it says it will meet EPA and carb requirements. Can't use it in Cali, but here in Florida we don't monitor the emissions yet. Do you guys think this will keep my CEL off?

If it does not then this will fix it:
Oxygen Sensor Spacer (CEL Boss)