I have a 02 Disco, with 150k on the clock. I have a check engine light with no driveability
issues. I cant get the diagnostic port to work. I tried the fuses #20 under the steering wheel. I don't think I am getting power to the connector port. It appears that this problem
has come up before on this forum. Has anyone out there resolved it?

Thank You

 

Well I have a similar problem, as mine if I get in the truck with the ultra guage plugged in, it might work. If it doesn't I have to unplug the UG and try replugging it in several times and hoping it comes on and then have to wait for it to connect back to the truck. As you stated I checked the fuses and all good. So maybe we're in the same boat

 

Bad ground wire for the OBD port. I think there was a service advisory about it, and the grounding stud that wire is attached to being prone to corrosion or something.

 

So that being the case, I could run a new wire to a better ground and voila problem solved. Never thought to check the ground. Thanks

 

And if that doesn't fix it, try spraying some electronic parts cleaner in the plug and on the ground. Should help clean up any more corrosion that might be around.