I just recently had my check engine light come on and had a friend scan it. It came back to catalytic converter problem. Was wondering if anyone had recently replaced their cat converter and whether or not they went with oem or aftermarket part. Any ideas on cost and if its usual for the cat to go at 95,000 miles. Was wondering if it could possibly be faulty oxygen sensor causing code as i just recently used chevron techron fuel additive to clean fuel injectors. Would either have any symptoms with the way the car is running. Appreciate any feed back. Thanks

 

it wont be an O2 sensor. Cats wear out, like anything. More if you tow regularly.
you wont be able to find any in the aftermarket. And last I checked, I think the factory cats (it should be 2 combined into a "y" pipe) were about 800 bucks.

also, dont EVER waste money on fuel additives. They are 100 percent worthless and NEVER, EVER needed.

 

What Error Code do you have?

P0431 and P0421 are for the left and right small (tiny) pre cats that are part of the exhaust manifold downpipes. I right one failed at about 110K and my left one just died at 150K. There are tons of places on-line that list Montero aftermarket cats but last time I looked these are all for the secondary large single cat. I haven't seen any postings of those having failed.

I had a dealer replace my right side for around $900. ($650 for parts alone) This time I've found an independent muffler shop that says it can weld in a tiny universal replacement for $350. I'm going to give them a shot at it.

My dealer swears that the 431 and 421 codes are always for the cat, not the O2 sensor. He was right the last time but it would be cheaper to try replacing the sensor first. However I've seen posts here of people having trouble with non-oem sensors so you're still talking about $200 + just to see if it's the sensor.

My dealer also said it's OK to drive with the bad cat - emissions will be higher but the only other symptom will be slightly lower fuel mileage.

Hope this helps

 

Thanks for the answers guys. Im going to my buddies shop to replace plugs and wires tonight because their due, I will also try and get the code from the scanner.

 

you will NOT get codes for failed cats due to O2 sensors. In fact, the fact that you get cat. codes pretty much ASSURES that the O2 sensors are functioning PERFECTLY. Also, there are no fewer than 8 codes for the O2 sensors themselves which will pop up if you do actually have problems with them.

also, you will NOT lose mileage. In fact, you wont lose anything. Except maybe your mind by staring at the illuminated light constantly.
You WILL pollute more. And if you live in a state that has emission testing, you will fail just due to the light being on.

 

I removed my cat converter when I installed a free flow filter then changed my exhaust to borla turbo mufflers, i never got the check engine sign or the exhaust has a stronger smell i guess because of unburnt fuel, but increased my mileage to about an additional 30 to 40 kms (total)

 

Cool, thanks again. Didn't want to waste any money testing to see if the O2 sensor was bad and not the cat. Code is cleared, now Ill see how long it takes before the light comes back on and will eventually have to replace cat.

 

If your situation is like mine and others I've heard of, clearing the codes works for some time and then the lamp comes back on more frequiently until finally you won't be able to clear it. As I recall the process took about 3 months on mine.

You might want to invest in a basic OBDII scanner so you can reset yourself and diagnose future problems. (Great to take along when shopping for a used car as well) They're not that expensive any more at Kragens, Pep Boys, etc.

Ron

 

i recently brought my 2003 ltd
after going to the dealer and asked him to print out all the work they have done

1 of the oxygen sensors was replaced

1 week later i floored the car down the highway
the next day a yellow light comes
on


the dealer said it was another oxy sensor

he said dont worry book it in at the nx servicr

 

we put a small strip of electrical tape over the light. If I knew for sure that aftermarket mods at the small (not the big one) cat would cure the condition and improve mileage/performance, I'd do it, but only if I knew others are doing the same thing with the same parts...