Experiencing a no power issue at your 2005 Yukon’s OBD2 port can be frustrating, especially when you need to run diagnostics. A non-functional OBD2 port prevents you from reading trouble codes, hindering your ability to understand and fix potential problems with your vehicle. Fortunately, this issue is often simpler to resolve than you might think. This guide will walk you through the troubleshooting steps, starting with the most common and easily addressed cause.
A frequent culprit behind a dead OBD2 port is a blown or faulty Fuse 13, located in the underhood fuse box. This fuse is crucial as it supplies power to both the OBD2 port and the cigarette lighter. Even if a fuse appears visually intact, it can still be defective. Therefore, the first and easiest step is to replace Fuse 13 with a new 20 Amp fuse.
Image: Wiring diagram illustrating the power circuit for the OBD2 port and cigarette lighter in a 2005 Yukon, highlighting the role of Fuse 13.
After replacing Fuse 13, check if the OBD2 port is now functioning and if the cigarette lighter port has regained its 12V power. If the issue persists, the next step involves using a multimeter to diagnose the electrical flow. Set your multimeter to DC Volts and ground the negative lead. With Fuse 13 in place, use the positive probe to test both exposed pins of Fuse 13. You should read approximately 12V on both sides.
If you are not getting 12V on both sides of Fuse 13, switch your multimeter to Ohms. Connect one end to the load side of the Fuse 13 contact in the fuse box (the side without voltage) and the other end to pin 16 of the OBD2 port. A reading of zero ohms indicates continuity, meaning the wiring is intact. If you don’t see zero ohms, there’s likely a break in the wire between the fuse box and the OBD2 port. In this case, tracing and inspecting the wiring for damage or breaks will be necessary to restore power to your 2005 Yukon’s OBD2 port.
By systematically checking Fuse 13 and testing the voltage and wiring continuity, you can effectively diagnose and often resolve the “no power at OBD2 port” issue in your 2005 Yukon, enabling you to proceed with necessary vehicle diagnostics and repairs.
