Can my 2003 Toyota really have a bad catalytic converter?

Please bare with me, as I feel I need to explain the chain of events:

I have a 2003 Toyota Matrix and my engine light keeps coming on. Over time, I’ve logged that it comes on about 600 miles after I get it “reset.”

The first time this happend, the Toyota dealer said it was my catalytic converter, estimated cost to fix was $1,000+. They reset my engine light and said if it came back on immediatly, that was definitely the problem.

Well it didn’t come on until about 4-6 months after that (time increments have decreased a bit since then). So I just took it to a place that does the diagnostic for free: same reading. 420 was the code I believe.

I’m currently in Virginia, but when I visited home in PA I had my mechanic there look at it. He ran the diagnostic without the light being on, and nothingshould be fine…

It eventually did come back on, and I’ve had it reset a couple times. This time, I figure I really need to do something. So I took it to a local shop last night who told me it’s my rear oxygen sensor AND converter. Total of about $1300.

I’ve been talking to people and they think there’s no way it could be my converter on a 2003. However, it has 98,000 miles on it.

Is there ANY way there could be something else triggering my light to come on? And if so, where can I take it to find out for suer? I hear the cat. converter is sometimes the “default” code that comes up.

As a poor recent grad, any information before I jump to conclusions would be MUCH appreciated!

Here’s the deal, the longer you run the car in this state the more you destroy. The rear o2 sensor is ruined since the emissions system is not working correctly.

Converters typically go much longer however if there is an emissions problem upstream of it gets ruined. Ignoring the possibilities only ruins more things (eg rear 02 sensor). My then finance now wife took the same route on a front O2 sensor code which in turn destroyed the cat converter and the rear o2 sensor. It eventually lead to stalling after driving at highway speeds and she took it in. Her dad told her she could wait on Check Engine Lights unless flashing. Hers would flick on/off every so often for a week at a time. She let this go on for a year.

She lucked out and found Honda had an oddball warranty due to EPA violations for 8yrs/150,000 which Honda picked up the $1600 tab for fixing it all.

Your vehicle has 3 catalytic converters on it. Do you notice any rattling when your driving coming from the converters? Any physical damage to the converters? (run over something) You could also have a mechanic perform a back pressure test on the converters as well as a temperature test using a pyrometer. The rear of the converter should be about 100 degrees hotter than front on a properly operating engine. The only thing the temperature test will reveal is whether the engine is operating properly or not and not whether the converter may or may not be bad. The back pressure test is more definitive in identifying catalyst failure however if the catalytic converter has indeed failed you must find out what caused the converter to fail in the first place. If the shops you are taking your vehicle cannot find the underlying cause you need to keep looking for a shop that can. Toyota from my experience, have a good reputation on their converters however your vehicle does have 3 converters so good luck!

We need to know what exact code is being triggered. I should be in the form (P0123).

Next I fear you may be a little late, or maybe just about to be too late for a free converter. The converter has a longer warranty than the rest of the car. Make sure you check that one out.

As for being too young for a converter, never. You can kill one in a few hundred miles if you try. Generally that happens when someone ignores a CEL.

Your are right about a few things. Something does need to be done, and you don’t need Toyota to do it.

Has your can had any other problems that you know of?

I took it as being, P0420 Catalyst System Efficiency Below Threshold (Bank 1)

Thanks for this information, I’ll be sure to ask the next place I take it to do this back pressure test/temperature test. And no, I don’t hear any rattling or strange noises.

That’s exactly what it’s been in the past. Not sure exactly what it was this time, at the moment.

You can always try just replacing both O2 sensors to see if that fixes it first, 100k is about how long O2 sensors usually last anyways in my experience. If that doesn’t fix it then its new catalytic converter time.

I believe that what this means is that the rear sensor is not measuring a significant difference from the front converter so it thinks the converter is not working. It may be only one of the O2 sensors. There are tests for the sensors and before the dealer or any mechanic suggests replacing the cats, they should test the sensors first.

O2 sensors generally never go bad. When o2 sensor code appear, it?s generally do to a problem up stream.
My question is, has the car had all its recommended scheduled maintenance done? You know, like replace the fuel filter every 15,000 miles, change the oil every 3,000 miles, Major service every 30,000 miles (most important). The reason I ask is that I have seen this scenario many times, after about 90,000 miles of neglect, the engines slowly start to run poorly but not enough to notice. The results are that the Cat plugs up and code pop up?
Note that so manufactures clam that tune-ups are not need until 100,000 miles. This is 100 % bull crap. This is a marketing scam to make the consumer think that they have a better product. The truth is that all the parts are the same, they still wear out and need to be replaced or you will be buying things like cats.

if you do have to replace the cats and o2 sencors have a muffler place do it. it will most likly be your best bet to get a good price on the work.

hope this helps
mopar man

Wrote you earlier with a reply. I am adding a great article I highly recommend you print and take to your mechanic. Make sure he follows there procedures. Good Luck!

Converter Diagnostic PO420 Code
Mostly By Ken Shafer Jr. From Muffler and Pipe Advice with some additions by me

Obtaining converter PO420 (Catalyst System Efficiency Below Threshold Bank 1) on initial diagnostic scan does not always indicate converter failure. Further diagnostics techniques must be performed to determine actual converter failure since this code is the end result in the OBDII diagnostic and requires further explanation.

  1. Be sure the PO420 code is the only code present.
  2. Check vacuum lines.
  3. Check gas cap and vapor canister line (if present)
  4. Check intake for gasket cracks
  5. Check MAF for leaks.
  6. Check oxygen sensors; performing ?Bench diagnostics as required by manufacturer. ( To little fuel is a lean condition, which raises combustion temperatures and in turn raises exhaust temperatures. Extreme temperatures lower efficiency of the catalyst and can trigger the PO420- DTC. At temperatures above 2100F the catalyst will begin to melt down, permanently destroying the substrate. Too much fuel entering the exhaust system does two things: 1. Can coat the substrate, cooling it as well as protecting the precious metals (which cause the catalytic reaction). 2. A spark enters the converter and ignites the fuel, at which point it turns into a secondary combustion chamber, destroying the catalyst (usually glows red).
  7. Once all DTCs are fixed, clear the codes and start the engine. Warm the engine until water temperature is stable. Increase engine speed for about 3 minutes, usually between 2500 and 3000rpm; this will help converter light off. After this, look at the wave forms between the front and rear oxygen sensors. If the front O2 wave form is switching from high to low (rich to lean) and the rear is close to a straight line, the original converter should be OK. If the rear O2 sensor is mimicking the front one, the converter most likely took damage and may need to be replaced.
  8. Complete a drive cycle and have converter monitor ready. Follow manufacturer guidelines for the correct drive cycle.
  9. Once drive cycle is complete. When you scan vehicle the only code present is the PO420 you should look at the freeze-frame data. This will tell you the conditions that were present when the DTC was set (vehicle speed, engine speed, O2 readings and fuel trim, among others but these four are the most useful. Looking at the fuel trim can tell you a lot without telling you too much. I know it sounds cryptic, but here?s an example: the only code is the PO420 but the fuel trim is high usually above +8%, but this can vary, and one should consult a repair database for proper percentages. You already know that the engine is getting extra air into the intake and the ECM is compensating for this by dumping extra fuel into the intake. When this condition is present I look for any type of vacuum leak, intake leak or a dirty mass-air-flow (MAF) sensor that could be the cause of this problem. If the fuel trim is low-usually below 8%, but this can vary the same as a high fuel trim-you know that the engine is getting extra unmetered fuel into the intake and the ECM is compensating by leaning out the fuel mixture. This is usually caused by either a stuck fuel injector or a bad fuel-pressure regulator.
  10. Once the problem has been identified the repairs should be made, and after the warm-up process has been performed the vehicle should be tested to ensure that no other codes arise. If the fuel trim looks within range it is time to look at the O2 values. The front O2 sensor should be switching from rich (over 600mV) to lean (under 300mV) and the rear O2 sensor, or converter monitor, should be a nice, smooth line with minimal variance in mV. When looking at the values of the O2 sensors pay particular attention to the switching rate of the sensors and be sure that neither the front nor rear sensor drops out or spikes for extended amounts of time. If either a slow switching rate or spike/drop-out happens by the O2 sensor may be starting to deteriorate-or as a lot of people say, ?it has become lazy? and may need to be replaced. If the O2 is determined to be lazy, remove it and check it for any contamination, usually by oil or antifreeze; if they are present, check the catalyst to ensure that it is not contaminated or poisoned. If so converter replacement will be necessary by not until the engine is repaired and the poisoning agent is no longer entering the exhaust, for this will lead to premature converter failure.
  11. If none of the above conditions is present and the engine is at operating temperature look at the front and rear O2 sensors. If the rear O2 sensor is mimicking the front one the converter will most likely need to be replaced; there are only a few other easy things to look at.
  12. After reviewing all the data and determining that there are no outside conditions causing the PO420 DTC, it is time to raise the vehicle and inspect the converter. Look for: Impact marks on the converter, if no, inspect the body of the converter to see whether it is discolored, indicating that the converter has been overheated. If this is the case you need to determine what caused the overheated condition ask the customer if they have had recent repair work, if they have you can proceed to replace the converter. If they have not had repair work performed then additional diagnosis may be needed.
  13. This is when you look over Technical Service Bulletins (TSBs) and the diagnostic flow chart for the specific application.
    14 Finally, drop the faulty converter and visually inspect the insides again, checking for fuel, oil, antifreeze or excessive carbon deposits. If they are present, again further engine repairs may be needed before replacement of the converter. If not, you can be relatively certain that replacing the converter will solve the PO420 DTC and the customer will not be back in a week with the nasty PO420 code again.

Wow, thank you so much…thanks to all for your responses. I took it somewhere else this week, and he said I have a Low Emissions Engine, so they don’t even make after market parts for my matrix. Maybe I’ll take this article to him…that won’t be insulting, will it?

It might be expecially if he/she does not have a code reader/scanner that can do the freeze frame reads of the computer data. You will have to make a judgement call as to whether this mechanic would take advice well.