I didn’t realize you were trying to use the Postman Collection Runner.
Have you been able to successfully run a single PUT request? If not, I would try just to make sure the request even works. Also, can you please share the Response Body you’re getting?
Here’s what I did to successfully run 5 iterations of a PUT request via Postman Runner:
Step 1. Make sure the PUT request works:
Btw, in Headers I only have Content-Type set to application/json. And in Tests I’m only checking whether or not the response status I get is 200:
pm.test("Status code is 200", function () {
pm.response.to.have.status(200);
});
If you look at the Test Results in the screenshot above, you’ll see that this test passed.
Step 2. Cool. Now that I know my PUT request works, I’m going to turn the values of name & job into variables. This way, Postman Runner will be able to map every row of name and job from my .csv file to these variables.
My .csv file looks like this:
Step 3. Now let’s use Postman Runner!
Awesome, every PUT request received a 200 response status:
And if we look at the Response Body of one of the logs in our Console, we’ll see that the information we were hoping to update was indeed updated:
Btw, I learned about these steps from this video by The Testing Academy 
.