Reset check engine light 98 mercury marquis?

To reset the check engine light on a 1998 Mercury Marquis, you can disconnect the negative battery terminal for about 15 minutes. This will clear the engine codes stored in the computer. Alternatively, you can use an OBD-II scanner to erase the codes if you have access to one. However, if the underlying issue causing the light to illuminate is not resolved, the light may come back on.