1. Make sure that the engine is off and the ignition key is turned to the "Off" position.
2. Find the diagnostic trouble code (DTC) connector. In the 1993 Volvo 960, it's usually located under the hood, near the battery. It's a black or gray plastic connector with a cover.
3. Remove the cover of the DTC connector.
4. Inside the connector, you'll find two metal terminals labeled "A" and "B."
5. Connect a jumper wire between terminals A and B. You can use a paper clip or a piece of wire for this purpose.
6. Turn the ignition key to the "On" position, but don't start the engine.
7. Leave the jumper wire connected for at least 10 seconds.
8. Turn off the ignition key and remove the jumper wire.
9. The check engine light should now be reset.
Note: If the check engine light comes back on after resetting it, it means that there's still an underlying problem with the vehicle. In that case, it's recommended to have the vehicle diagnosed by a qualified mechanic to identify the root cause of the problem.
