OBD2 port still doesn't work
 

2002 Disco 2, I have a Service Engine Light but cant get the code reder connector to work. No light of my code reader. I have already done the following:

1. Checked all the fuses in the box near the steering wheel

2. Carefully cleaned the connector metal contact points with cleaner and a small knife

3. Rerouted the brown ground wire, and checked for continuity. Now OK

4. Checked the purple power in wire but only got .9 volts on the multimeter ?

I see this is a common problem on these models; has anyone figured it out?

Sounds like you've got a broken wire or corroded connector somewhere. What you can do, if you just want pull the codes, is back probe pin 16 and jump 12v to it. Assuming the other wires are good, you'll be able to use your scan tool. It's not a permanent fix, but it will work in a pinch.
Good luck.

I had the same problem on mine and tracked it down to a shorted connector under the HVAC Blower on the passenger side. Water was going under the heater air intake plenum, dripping into the blower motor then dripping on the bundle of wires and connectors that runs across the firewall under the blower motor. The connector that shorted was in that bundle of wires. It also took out the fuse for the garage door opener and accessory plug.

Start studying the electronic diagrams in the RAVE and limber up to do some under dash contortions to fix any shorted connections.