Having problems with your GMC Sierra 2500HD ?
Code shows a large leak at the EVAP - Sierra 2500HD GMC Cars & Trucks
Not sure of your year or model but alot of times a code like that could just be a bad gas cap. That is cheap and easy place to start. You will probably need to have someone turn the light off with a scanner after repalcing the cap. Also depending upon the year and model you have there could be a pressure switch in the top of your fuel module that can fail and cause your code.
Repair Help & Product Troubleshooting for GMC Sierra 2500HD
Tips for a great answer:- Provide details, support with references or personal experience .
- If you need clarification, ask it in the comment box .
- It's 100% free, no registration required.