What can I do about a ECU code 12?

What is your question?

The check engine light on my 89 CRX recently started coming on, usually after I've been driving it for awhile. When I got the chance I checked what the code was and it was 12. After doing some looking I found out that its the EGR Lift Sensor, but I don't know what that means for my car. How will that affect my car and how can it be fixed?