Experiencing a no power issue at your 2005 Yukon’s OBD2 port can be frustrating, especially when you need to run a diagnostic scan. Without power to this crucial port, connecting a scanner to read trouble codes becomes impossible, hindering your ability to diagnose car problems effectively. Fortunately, this issue is often simpler to resolve than you might think. This guide will walk you through the primary culprit and how to quickly check and fix the “no power at OBD2” problem in your 2005 Yukon.
Understanding the OBD2 Power Circuit in Your 2005 Yukon
The On-Board Diagnostics II (OBD2) port in your 2005 Yukon requires power to operate. This power is essential for your scan tool to communicate with the vehicle’s computer systems. A common point of failure for OBD2 port power loss is a simple fuse. Specifically, Fuse 13, located in the underhood fuse box, is often the key to restoring power. This fuse not only powers the OBD2 port (specifically pin 16) but also the cigarette lighter port. This connection is a useful diagnostic clue, as checking your cigarette lighter can quickly indicate if Fuse 13 is the problem. If neither your OBD2 port nor your cigarette lighter is working, Fuse 13 should be your first suspect.
Step-by-Step Troubleshooting for OBD2 Power Loss
Here’s how to troubleshoot and potentially fix the no power issue at your 2005 Yukon’s OBD2 port:
Step 1: Inspect and Replace Fuse 13
The first and easiest step is to check Fuse 13 in the underhood fuse box.
- Locate the Underhood Fuse Box: Refer to your Yukon’s owner’s manual for the exact location of the underhood fuse box. It’s typically under the hood, often on the driver’s side.
- Identify Fuse 13: Consult the fuse box diagram (usually printed on the fuse box cover) to locate Fuse 13. It is generally a 20 Amp fuse.
- Visual Inspection: Remove Fuse 13 and visually inspect it. Look for a broken filament inside the fuse. However, fuses can sometimes be faulty even if they look visually intact.
- Replace Fuse 13: Even if the fuse looks okay, it’s best practice to replace it with a new 20 Amp fuse. Ensure you are using the correct amperage.
This image shows the 2005 Yukon OBD2 port and cigarette lighter wiring diagram, highlighting the circuit powered by Fuse 13.
Step 2: Test for Power at the Cigarette Lighter and OBD2 Port
After replacing Fuse 13, check if power has been restored:
- Cigarette Lighter Test: Test your cigarette lighter (or auxiliary power port) with a phone charger or another 12V device. If it now works, this is a good sign Fuse 13 was the issue.
- OBD2 Port Voltage Test: Use a multimeter to check for voltage at the OBD2 port.
- Set your multimeter to DC Volts.
- Ground the black lead of the multimeter to a known good ground (a clean, unpainted metal part of the vehicle chassis).
- Probe pin 16 of the OBD2 port with the red lead of your multimeter. Pin 16 is typically located in the top right corner of the OBD2 port.
- You should read approximately 12V DC if the port is receiving power.
Step 3: Advanced Troubleshooting (If Necessary)
If replacing Fuse 13 doesn’t restore power, further investigation might be needed.
- Fuse 13 Voltage Test: Use your multimeter to check for voltage directly at the Fuse 13 location in the fuse box. With Fuse 13 installed:
- Ground the black lead of your multimeter.
- Probe both exposed metal contacts on top of Fuse 13 with the red lead.
- You should see 12V DC on both sides of the fuse. If you only see voltage on one side, or no voltage, there may be an issue with the power supply to the fuse box or the fuse box itself.
- Continuity Test: If you suspect a wiring issue between the fuse box and the OBD2 port, you can perform a continuity test. (Caution: Disconnect the negative battery terminal before performing a continuity test to prevent electrical damage.)
- Set your multimeter to Ohms or Continuity mode.
- Connect one lead of your multimeter to the load side contact of Fuse 13 in the fuse box (the side that did not show 12V in the previous test).
- Connect the other lead to pin 16 of the OBD2 port.
- You should read close to zero ohms or hear a beep (depending on your multimeter), indicating continuity. If not, there’s a break in the wiring between Fuse 13 and the OBD2 port.
Restoring OBD2 Power and Next Steps
Hopefully, replacing Fuse 13 will resolve the “no power at OBD2” issue on your 2005 Yukon. Once power is restored, you should be able to connect your OBD2 scanner and retrieve any stored trouble codes. These codes will provide valuable information for diagnosing the underlying issues with your vehicle.
If you continue to experience problems or are uncomfortable performing these steps, it’s always recommended to consult a qualified automotive technician. They can perform a more thorough diagnosis and repair. Good luck, and we hope this guide helps you get your 2005 Yukon’s OBD2 port working again!
