I was looking at the engine codes on an 850 GLT wagon due to the check engine light being on. The result was 4-4-3, or catalytic converter efficiency. Has anyone else received this code, and if so, what was your solution?

thanks in advance!

Eric R.

I had the equivalent code on my Ford. Please follow Klaus' advice and check for other codes then address them before suspecting or investing in the cat. Also look for an exhaust leak even if very small which can upset the flow to the oxygen sensors (as well as vacuum leaks etc). These things could act like a failing cat.

I got the catalyst efficiency code once in a while and reset it. This car has 2 cats with separate efficiency codes. One code would set, then the other in a little while. This pattern would return after a month or 2. Eventually it showed up more and came to the point that the codes would come on after just a day or 2.

I thought it was unlikely both cats would go bad at once so I looked for everything else I could think of first. Finally I had the 2 catalytic converters replaced. No codes of any kind have come back so far (4 months).

The car had only 75K miles and I thought that was early for cats. On the other hand the engine had a history of running rich which would contaminate the cat, and the engine on this model is not known as one of the world's most efficient designs. People tell me the cat CAN be a lifetime component but may not be.

I am surprised that this is your only code. Could you erase it and it came back? Usually, it means that the O2 sensors, front and rear, couldn't keep the readings in check. If there are no vacuum leaks (usual suspect) then it is probably the rear O2 sensor.
Cat replacement would not be my first choice, too expensive and they usually last over 200K miles.

Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)