Volvo: problem with lamda light, lambda sensor, mileage

Question
Hello Ray.... I recently had an exaust leak in my 84 240 welded, however after leaving the exaust shop, my lambda sensor was on.... I replaced the sensor, and the light didn't go out.  Could the welding on the exaust have caused a problem with the lambda computer?  The car still started fine for 2 months, but now I'm having problems.

Answer
Jose,
The Lamda light is a mileage counter. Behind/under the dash there is a small mileage counter with a cable and wire that goes to the back of the dash cluster. Find that small black box look for a cover held on by a single screw, remover that cover and push the button, that should reset the counter. I think it comes on every 30,000 miles. That would not have any affect on the running of the vehicle.