I have a friend who's 2005 Expy with 115.000 miles is throwing a code that says their Catalytic converter needs to be replaced. There are also apparently transmission problems.

Can anyone here tell me how the heck a Catalytic converter can go bad? It is not that many miles and the moderate near future I never thought there would ever be an issue with one of them. Unless the motor is just way out of wack and sending all kinds of junk out.

But I can not understand how just the Catalytic converter is bad. The transmission not doing well would cause a problem???

Or maybe the mechanic is just going off the code only and not much else. The code is P0430

I am just confused. I did not see any issues of such searching on the forum.

Thanks all.

 

Driving with the Service Engine Soon light flashing.

Leaking head gasket can coat the element with anti-freeze.

Burning excessive amounts of oil.

Using the wrong type of fuel.

You didn't specify the exact codes that it is throwing?

 

Sorry, I added the code after I got it, but after I posted it.

They have none of those issues with their vehicle. But thanks for the input as I was drawing a blank on how. And yes, with any of those it would clog it.

I looked up the code and man... It is not a converter problem. I think they need to replace their plugs and O2 sensor. They have only replaced 2 plugs since owning and it is "only" 100,000 mile plug. So it could very well be, they are not firing perfect and it is causing the sensor to read what it is.

 

Our '03 5.4l Expy with 128k just had the cat go bad. I suspect only one side, but somehow it got clogged and restricted the exhaust flow. I haven't cut it open, yet, but if it's just the precat I'm going to gut the precat and try it out. Long before the exhaust got really clogged there was a ticking noise coming from the end of the right precat, something tapping inside the pipe. When the ticking stopped after a few months the restricted exhaust got worse. Replaced the cats and it runs great.
Our '89 E-350 5.7l had the ceramic honeycomb inside the cat break into pieces and clogged the output. When you tapped on the casing you could hear the pieces rattling inside. There was no rattle in the Expy cats.
Our '92 Explorer with 218k still has the original cat.

 

DTCs P0420/0430 are not indicative of a clogged or restricted cat, they indicate a cat that the PCM has determined is no longer doing its job. Nothing more, nothing less.

An ignition/fuel control system that is in poor repair may cause the conditions for either the cat to be damaged of for readings that falsely indicate a failure of the cat.

 

The main reason catalytic converters go bad is you have some type of fuel, or ignition or head gasket problem with the engine. This usually is caused by dirty air filters, worn plugs, bad coil packs, dirty injectors, vacuum leaks, or leaking coolant that contaminate the O2 sensors with soot and unburned fuel, then the O2 sensors get lazy (don't read properly quickly enough) causing incomplete combustion on most cylinders resulting in unburned fuel in the exhaust that continues to burn in the hot converter and winds up melting the substrate material of the catalytic converter.

Moral of the story is, air filters, spark plugs, spark plug boots, coil packs, and O2 sensors, vacuum hoses, belts, and even fuel injectors are items that can wear out, and if you don't stay up on your maintenance and add that bottle of injector cleaner every now and then your catalytic converter may get melted and stop letting exhaust gasses flow through it. So follow the recommended maintenance schedule, (especially coolant and oil changes); if the check engine light comes on get it looked at, and if you do, odds are that your high quality Ford/Lincoln is going to last a good long time.

 

I have an 05 Expy i bought new that has 98k miles on it right now. I had been having problems with engine hesitation at high speed acceleration for over a year. Back in Apr 2010 dealer replace two coils under my extended warranty (not Ford), Drove ok for a while but then would hesitate again, took it in several times over the next few months and they replaced other coils also. I asked to have all replaced at once, but dealer said they can only replace what diagnostics said is bad because that is what the warranty would pay for. I did not want to pay for replacing the coils myself. At 79.9k miles dealer says both of my cat converters went bad and they replaced for free. But still had problem with hesitation. Service advisor finally recommended to perform tune up at 95k miles. Before then, one cat converter started rattling, and dealer replaced it free. At time of tune up, it test code P0430 popped back up and now they are saying the converter they replaced at 79k is out of warranty, and it would cost me to replace it now. It only had 12k warranty.

Based on what I have read in this and other threads, the bad plugs may have fowled up the converter. BTW, I did fuel injector cleaning, fuel and air filter replacements on a regular basis. I would like some feedback on this, since I feel the dealer should replace the converter since they were replacing coils so many times, sometimes the same ones and did not figure out the real cause. Now the converter is bad again.

 

Looks like your worn plugs cooked your converter. (this is what happens if you drive around for a long time with bad plugs or coil packs) My recommendation is to forget about trying to fight with the dealership to get another converter replaced under warranty as it's only going to get your blood pressure up or wind up costing you triple what you would pay elsewhere. Just bite the bullet, take it to any local muffler shop where they can replace whatever cat of the two is bad for around $250.00 (don't let them talk you into paying extra for an OEM converter as they are the same as the aftermarket ones) and then if you haven't already done so, install two new upstream O2 sensors as well that run around $50.00 each at any auto parts store keep this from happening again.