2004 Acura TSX - CEL points to CAT

We drive a 2004 Acura TSX. It’s been a wonderful car. Recently the check engine light has been coming on. The manuel says check the gas cap to make sure its on tight which we did. That seemed to fix it the first few times. But now it’s coming on an also going off and the gas cap doesn’t seem to effect it. I’ve had both a Honda dealer and a Acura dealer run a diagnostic on it and both have said the catalytic converter is failing. The Acura dealer said the part costs $1,700. I don’t think that includes labor, etc.
My question does it harm the car to drive it without replacing the converter? If it fails while we’re driving it, will it suddenly strand us.
Thanks! We enjoy & benefit from your column.

I don’t know what codes the dealers pulled from your car, so I don’t know what kind of failure of your converter is. But a converter that fails efficiency, may not make a difference in performance. It will pullute more. But if the converter gets plugged you will eventually loose power drastically and possible engine damage.

To add to tc’s Comments, get an estimate from an independent (not chain) muffler shop.

Based on what op posted earlier . . .

I would guess the dealer retrieved P0420 and/or P0430 codes

No, it won’t leave you stranded because of this code. My advice is to do nothing until/unless you have to take it through an emissions test, or start experiencing performance problems. If you have to pass an emissions test, I would try disconnecting the battery to clear the codes, and then seeing if there is a “sweet spot” of miles you could drive which would allow enough monitors to show “ready” without setting the CEL. You can buy a cheap scanner from Harbor Freight Tools, which will allow you to see if the monitors are “ready”.

For example, one of my friends had a 1998 Plymouth Voyager with an obvious misfire at idle, which we diagnosed as the head gasket leaking between two cylinders. Due to the difficulty of this repair, and the fact that the van was in poor cosmetic condition with high miles, we decided to experiment to see if we could get it through emissions.

What we found was that we could disconnect the battery, clear the constant CEL, and if driven more than 50 miles, but less than 100 miles, enough monitors would set as “ready” to pass the emissions test, and then after reaching 100 miles, the CEL would return. Unsure if this strategy would work on a 2004, because I believe 1996-99 can have two monitors show “not ready” but 2000 and up can only have one.

The problem with doing nothing about the catalytic converter is, the Check Engine light will be on all the time.

So if another problem should arise that would turn on the Check Engine light, you won’t know it. And that new problem might damage the engine/transmission.


In most/all states . . . the catalytic converter readiness monitor on this particular vehicle must be complete when you bring it in for emissions testing, whether it’s the plug-in kind or the full dyno run with tailpipe kind of test

You’re allowed to have one incomplete readiness monitor . . . and it can’t be catalytic converter

What you described earlier kind of works with certain evap problems which command the mil to be illuminated.