SOLVED - 04 yukon denali OBD port has power and scanner powers up but wont connect

Can't seem to find any info on troubleshooting the communication error on my obd port. I tried my scanner as well as the guys at Napa. The port powers up but nothing to connect. Any help on how to start the attack on this would be greatly appreciated.

We had this problem before on our 2500 Suburban; lines to the ECU were rusted. You are going to have to trace wires, unfortunately.

kingdom77 said:

Can't seem to find any info on troubleshooting the communication error on my obd port. I tried my scanner as well as the guys at Napa. The port powers up but nothing to connect. Any help on how to start the attack on this would be greatly appreciated.

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check the accessory fuse that powers the cigarette power port (usually the one closest to the driver), if the power port is not working then the fuse is burnt and that fuse also controls obd port communication. the obd port will always have power and ground regardless.

Same thing with my '02 Yukon. I saw that about the fuse on one of he Facebook pages. Changed the fuse and my OBD port works now. Never would have known.

I have power to the port, just can't connect. Disconnected both combs and still nothing. Powers up but no connection.

Watch some YouTube videos from "South Main Auto". He has dealt with this problem on numerous different vehicles. Unfortunately, it involves a lot of wire tracing and probing to figure it out. Most likely you have a corroded, broken or damaged wire somewhere. Some of the videos he found physical damage from hitting road debris, some were corroded from salty winter roads, and some had rodent damage/chewed wires. But if you watch his videos, you'll learn how to trouble shoot and repair this issue yourself. I hope you have a digital multimeter and a test light, because you'll need them.

Dumb question, but how do you know the scanner is any good?

Need some help, I failed Arizona emissions test on my 2001 because my OBD port has no voltage. Emissions and fuel cap and check engine light are all fine ... just don't have any voltage on the OBD and that's part of the test.

Looking above I see I need to check the South Main Auto YouTube videos and the cigarette lighter fuses, but can anyone add more information or suggestions? And can anyone tell me which fuses I should check (location, etc).

Meanwhile, I'll start tracing wires. Thanks in advance.

Scott in AZ said:

Need some help, I failed Arizona emissions test on my 2001 because my OBD port has no voltage. Emissions and fuel cap and check engine light are all fine ... just don't have any voltage on the OBD and that's part of the test.

Looking above I see I need to check the South Main Auto YouTube videos and the cigarette lighter fuses, but can anyone add more information or suggestions? And can anyone tell me which fuses I should check (location, etc).

Meanwhile, I'll start tracing wires. Thanks in advance.

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You guys absolutely R O C K.

I checked my 3X cigarette power ports and sure enough 1 of 3 was dead, no power. I swapped these 2X 15 amp fuses and the dead power port (pax side, far right) came back, but other 2 were dead. I checked fuse and sure enough SEO1 was burnt/failed. So I replaced and now both power ports have power, so maybe…… my OBD port will have power again I’ll get the Arizona MVD test again and pass Emissions. We’ll see. Tomorrow an update.

Passed Arizona Vehicle Testing and resolved the problem with No Voltage on OBD Port (OBD Connector Integrity) by replacing one of the two cigarette lighter fuses SE01.

All good.

Also, lesson (re)learned: Always check the fuse first even when you don’t think it’s the fuse!

Thanks for the help everybody!