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Check Engine light

On A Vovvo 2000, S40 will the check engine light reset it self after the new oxygen sensor is installed? My friend did not have the equipment to reset the system.

Try disconnecting your battery for 30 seconds. Make sure you have the reset code for your “anti-theft” radio if so equipped…

Yes in time after a new sensor is installed it will reset itself. It may take a week or two. However it will only reset IT the sensor was the problem.

Far too often sensors get replaced when the problem was what they were sensing. Are you sure the sensor was the problem and the only problem?

It will eventually go out, but the code reader a lot of auto parts stores use will also reset the light. Go to one of them and have them reset it. First try the store you purchased the O2 sensor from.

It usually takes some time for the sensors to automatically reset after the problem has been corrected. The amount of time depends on the vehicle. If you have a repair manual for the vehicle it will usually give you the amount of time required for the reset to take place.

Yes it will after so many driving cycles (running-drive-off) IF the problem was actually corrected.