I am new to this forum and would appreciate any help with this problem. I am considering purchasing a used 2000 Boxter (no S) with 29000 miles. On the test ride, the CEL light was on. The seller says it needs an O2 sensor, which he will take care of. I am worried the CEL light may be for some other engine/emissions problem.Am I correct in supposing if the sensor is replaced and the CEL reset, but the problem was not the O2 sensor, the original code(s) will still be available, andthe lightwill come back on after ??? miles/starts?.

Alicia

 

yeah.. If the problem was not fixed and it wasnt the O2 sensor, The light will come back on indicating the problem was not fixed and needs attention.

 

Thanks for the fast reply!Would anyone know how long it would take for the light to come back on? Is it as soon as you start the car after resetting the code? After 3 starts? After 25 miles?