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Pick a Catalytic Converter

We bought our 16 year old twins a 2004 VW Passat. Check engine light came on. We had a mechanic at Meineke tell us it was the Passenger side Catalytic converter. Wanted 1050.00 to replace it. The mechanic told me right side fine. Wanted to verify this was the problem. Took it to the VW Dealer they said I had a bad Catalytic converter on the DRIVERS side! Wanted $1300 to replace it. I asked him if the other one was bad or going bad. He said it was fine and he had run all the tests on it. My husband asked the neighbor down the street who works on car. His response to this was get rid of it. My husband said you mean the car, and he said no, the Catalytic Converter. HELP!!!

Well, I would say ‘sell the car’. That age Passat is rated “much worse than average” for reliability, it’ll cost you now and for years to come.

But don’t get rid of the cat, it’s illegal to do that.

I’d be more inclined to believe the guy at the dealership than the guy at Meineke.

But look at your copies of the shop orders and post the codes here. That’ll help.

Don’t get rid of the converter. No state emissions inspection could pass the car and a shop could not legally remove it. You’ll not get rid of the CEL that way, and it may make resale difficult.

CODE was P0143.

Your neighbor is one of those people who enjoys breaking the rules. Removing both catalytic converters without replacing them is a bad idea.

The code reader the Meineke guy used probably isn’t as sophisticated as the one they use at the dealership, so I would bet the dealership is right.

With the prices quoted, I would do the following:

Go to Meineke and ask what happens if they replace the catalytic converter for $1,050 and the CEL (check engine light) comes back on. If they are willing to give you a money back guarantee, in writing, go for it. Since they are probably wrong, you will probably have a new catalytic converter on that side for free. Then, see if they will replace the second catalytic converter for $1,050 with the same terms. If they won’t take that chance, make the same offer at the dealership. Tell them you want it in writing that if their replacement of your other catalytic converter doesn’t solve your CEL problem, you get your money back.

There’s a remote chance both catalytic converters are good, and that you have a faulty oxygen sensor (or two, or three, or four), in which case, you will have gotten both catalytic converters for free. Wouldn’t that be nice?

So with the small chance that its a faulty oxygen sensor and that being a cheap fix, should we have those changed before considering paying for a new cat conv.

I wouldn’t just replace parts that might be fine. The last time I bought an oxygen sensor, it was not cheap (about $200 each). However, you might be forced to replace an oxygen sensor or two. They often get fused to the catalytic converter from all the heat.

Go with what you know and see what happens.

Watch out with those chain-shops like Meineke, Midas etc.
Don’t let them do anything except their main line, in this case mufflers.
Even then it’s a crap shoot, like with AAMCO (All Automatics Must Come Out!)

Find a good independent shop that specializes in VW, or at least foreign makes.
No point taking an out-of warranty car to the dealer.

That’s a low voltage signal in Bank 1, sensor 3. Bank 1 is the side of the engine which has cylinder #1 on it - I can’t find a numbering diagram for the Passat, but if you can identify that cylinder, you’ll know which cat could potentially be bad.

But with just a low voltage signal and there is no efficiency signal (ie, you aren’t getting P0420, P0421, P0422, P0423, or P0424), I’d suspect the sensor and get it thoroughly tested before doing anything else.