G'day, I'm not sure if your model is similar to mine (1998) but when my engine check light came on my research indicated that it means a problem with the emissions of the vehicle. The easiest check to carry out before you spend money getting the computer checked is to inspect the rubber elbows on the vacuum tubes, particularly the elbow which is located under the intake manifold on the passenger side (drivers side if LHD) nearest the power steering pump. You'll need a good light to see in to where it is located. A quick inspection of mine revealed a broken $8 rubber elbow. I bought an elbow kit and replaced the lot then took the car in and had the light reset for $50 at my local Volvo Specialist (not Volvo Dealer). Problem solved. Cheers and hope this helps.

Greg M
Toowoomba
Australia
VCQ

If this is related to a failure of the TPS, Volvo should (can be convinced to) replace the cat as part of the recall/update. Or at least the dealer here has done so on one occaision that I know of.
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01 V70 2.4 M5 and a Mini

Some dealers for some reason believe to think that they can get away with trying to sell you a catalytic converter when you don't need it. In general, the cat should last you the life of the car, unless your car has been running very poorly over that time. CEL usually comes on for: O2 sensors (2 of them), Mass Air Flow sensors, a bad vacuum leak, a bad gas cap.

There are some non-dealer Volvo repair shops that you should try out to get second opinions. In the Seattle, WA area, Daisywagon in the University District is the place I take both my 1986 240GL wagon, and 1999 XC70. They are great, fix only what needs to be fixed.

Keep yor eye on the timing belt. I speak from $3500 worth of experience.

Cats usually will last the life of the car unless abused terribly, like filling up in Mexico with leaded gasoline.
It would be nice to know what the codes are, but most often it is a bad vacuum line around the intake manifold.
If you get the cat replaced, of course you should replace both O2 sensors at the same time. Much easier to put new into new before the heat of the exhaust seals the threads to breaking point. Besides, putting the O2 sensors on new parts can be done off the car, making the install much faster.
Beware of the code that says "Cat damage may lead to failure", this happens after multiple misfires and will not hurt the cat unless left unfixed. Misfires usually happen with old plugs, wires, etc. Some times with a bad fuel injector.

Klaus
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Please answer, we need to know if the advice is good or bad. The 164 has a new home, all I am left with are 2 turbos :)