No power to OBD2 port?

2018 GMC SIERRA
88,000 MILES • 6.2L • V8 • 4WD • AUTOMATIC
Avatar
MLUCAS47
Failed inspection because there is no power to port so can't do MA emissions test. Contacts look good, auxiliary power ports have power (including cigarette lighters). Thinking it is a blown fuse, but I do not know which one.
Thanks
Mar 2, 2025 at 7:54 AM
Advertisement
Avatar
AL514
  • ✓ASE Certified Mechanic
  • 5,541 POSTS
  • ASE Certified Mechanic
Hello, the fuse for the DLC (pin 16) is the DLC/DSM Fuse 10amp in the left side dash fuse panel, I will post a wiring diagram as well. but check pins 4 and 5 for good Ground as well, when checking pin 16 for power, use pin 4, then pin 5 for ground to make sure it's good.
Mar 2, 2025 at 10:07 AM
Avatar
AL514
  • ✓ASE Certified Mechanic
  • 5,541 POSTS
  • ASE Certified Mechanic
Here's the fuse you're looking for and the pinout for the Data Link Connector.
Images (Click to enlarge)
Professional Diagram for 2CarPros Members
Click here to log in and view diagram.
Professional Diagram for 2CarPros Members
Click here to log in and view diagram.
Mar 2, 2025 at 10:13 AM
Avatar
MLUCAS47
  • MEMBER
  • 2 POSTS
DLC/DSM was position 25 and the fuse was indeed blown.
Thank you very much!
Mar 2, 2025 at 10:28 AM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.