Toyota Camry aftermarket catalytic converter


I have had 2 Toyota Camrys (1997 and 1998 LEs that have had the catalytic converters changed- once for a repair after an accident and once because the pipe needed to be replaced. In both instances, after 6 mos or so after replacement, the check engine light came on and the diagnosis was an underperforming cat converter. The Toyota dealer insists this is due to too much back pressure in a converter not really designed to meet the standards of the engine, and that continued operation would eventually result in engine failure.

In the instance of the repair job, the body shop replaced it with a

toyota OEM part and all was well. In the instance where the pipe was rotted and the converter was replaced, after the first time the light came on the chain that installed it said that there is only an incompatibility between the converter and the vehicle’s electronics, but that the converter works just fine. The light has come on again about a year later, and

Toyota still maintains a Toyota converter needs to be installed or the engine will be damaged.

Who is right?


The “chain” was full of bull. The converter has no electronics. There is an “upstream” oxygen sensor that checks the oxygen level and tweaks the mix, and a “downstream” oxygen sensor that checks the level again and the ECU compares the signal to the first O2 sensor signal. If the modification of the signal created by the converter is insufficient, the CEL trips. If the CEL trips, the converter is not performing properly.

What I suspect happened is the “chain” jury-rigged (perhaps welded) in some “one size fits all” cat converter. And it was incorrect for your car. Midas does this.

A correct “direct fit” aftermarket converter is fine. Avoid the chain shop and have an independent shop reconfigure the exhaust system back the way it should be and install a proper aftermarket converter.

By the way, dealers ALWAYS say that only their parts will work properly. Because those are the only parts they can sell!


Aftermarket parts vary greatly in function, price, and longevity. Some are better than OEM while others are meant to last another year or so and may as well be called junk.

I would suggest finding an independent(Toyota concentric better) for a second opinion of the entire situation, its possible something else is not functioning that damages your cat converter. They also may have a quality aftermarket part in mind.


Thanks fo much for the advice. Sounds very reasonable.


Sounds good. That’s what I will do. Thanks!