Should I agree to submit a paper with my name as coauthor although I did not read and understand the whole paper? I finished my PhD in natural sciences in 2015. At some point during my PhD studies I did some measurements for some other scientists.

Now they are about to submit a paper containing my data, and I am listed as a coauthor.

I barely remember the experiments. I did not read the paper (yet).

Do I have to read that paper? Do I have to read it often enough to fully understand it? Should I disagree being listed as a coauthor?
Although doing a "service" by providing measurement data does not usually warrant co-authorship, some groups still decide to do so to show appreciation.

Many people in academia would accept this as it boosts their CV, and if anything wrong was found in the research after publication, the corresponding author has the highest authority.

I would give it a read and accept it if you are happy with the paper. If you are really worried, you can ask the authors to remove your name and explain you feel you did not provide a significant contribution.