2002 Lincoln LS Catalyst Code

Quoted From EndSupremacy:

+1 on both of your posts. I do believe it is most likely your cat. If you want to be sure, test your o2 sensors and make sure they are working fine. Also, check for exhaust leaks. You said you had some engine problems? It could possibly be that your computer was used to the engine running bad and now that it is running good, it’s reading lean or rich. Disconnect your battery and let it sit for 30-45 mins. Then re-connect it. The code won’t be there, but drive the car around. If it doesn’t come back, then you don’t have a problem. If it comes back, then do the tests. Just hope it’s not the cat. Don’t know about your car, but a cat for my car cost about $600, and that’s on ebay.

Excellent post!

Quoted From rice400:

It means the upstream and downstream oxygen sensors are reading similiar. The upstream should be switching back and forth from rich to lean while the down stream (after the cat) should be relatively stable. Its possible you have a bad cat, damaged or bad 02 sensor, exhaust leak…. among others

It’s possible that it’s the O2 sensors but it’s much more likely that you need catalytic converters.

If the vehicle had misfires prior to these cat. efficiency codes, the unburnt fuel may have damaged the cats as a result of the miss.

There are several ways of testing your cats such as using a pyrometer, exhaust gas analyzer or even looking at your post cat o2 sensor readings. They should both be a steady 0.45v if you look at your PID data.