1998 Volvo S70 GLT check engine light will not go out even after replacing the sensor.

Disconnect the battery over night and if the light comes back on after driving it a bit, it's still an issue. If it stays off then it's good. Sometimes CEL's take time (well, miles) to turn off on their own.

I say just go to your local auto parts store and have them check the codes on the comp they will connect to your vehicle then go home and punch in the codes make and model on Google and you'll get a answer to the problem ! Remember it could just be fluids , A sensor goes off for oil,radiator fluid,brake fluid and Trans fluid , the fix can be an easy problem !

I had the same problem. I have been told that the computer tests that the car has to pass to get the check engine light to go off after fixing the problem were written in 1996 by Bosch engineers and are extremely difficult to push a vehicle through. I had to take my car to Brentwood Volvo in St. Louis. They had the car for almost a week and were able to push it through everything necessary and get the CE light to shutoff. They charged me $99. This was only after I'd tried driving the car almost 300 miles and doing everything the other repair shop that fixed the problem told me to do. You might have to find a Volvo dealer in your city that has the expertise to beat the tests written by these complicated Bosch engineer thinkers that wrote the tests.