How to use coupon code on eobdtool.co.uk Posted on October 12, 2016 by eobdtool.co.uk How to use coupon code on eobdtool.co.uk: Step 1. Add product to cart. Step 2. Check out in your shopping cart. Step 3. Input the coupon code “XXX” into the red box as the following shows: Step 4. Now you recieve X% discount, for example 8% off.