I recently had a lot of work done on my 1998 XJ8.

I know my OBD port was working because some work I had done at a recent mechanic had used the port.

I use a Automatic device that communicates driving info to my cell phone.
(see www.automatic.com) This is just a simple plug in device and had been working with the car OBD port.

I had a starting problem, and thought it was the battery in which I had purchased a brand new one in May at VIP.

Took it back there, they said the battery was fine and the problem was elsewhere. VIP diagnosed the issue as a bad starter and replaced that and several wires, one of which had been burned?

At any rate, the car is fixed and everything works great. Especially being able to now start the car every time now.

Now I have noticed I have a dead OBD II port! The Automatic has failed to communicate to my cell and I do have a code reader and that will not power up when plugged in.

Any ideas what the problem might be?

Thanks for the help!

 

First look for a blown fuse. Fuse 13 in the driver side fascia fuse panel on my XK8. Yours should be similiar but no guarantees.

 

Hi Bruce,

If you don't have the X308 Electrical Guide, send me your email address via private message and I'll send you the pdf manual. I think the download link from this forum is currently down.

Looking at the schematic for the CAN & Serial Communications networks, pin 16 of the OBD II "Data Link Connector" should always have 12V battery power from Fuse 4 (5A) in the LH Heelboard Fuse Box.

Pin 9 in the OBD II connector should have 12V power when the key is in Position II (Ignition ON). That power comes from the ignition-switched Fuse 4 (5A) in the Trunk fuse box.

Pins 1 and 8 of the OBD II connector should switch to Ground when the key is in Position II. Those ground connections pass directly through the ignition switch to the Engine Management System ground stud on the cabin-side firewall/bulkhead, just right of center behind the dash (Ground FC17L on the schematics).

Pins 4 and 5 of the OBD II connector are both Logic Grounds and should always have continuity/very low resistance to the chassis/earth.

I'm attaching Figure 19.1 which shows the CAN and Serial Communications network connections. The Data Link Connector (OBD II port) is shown at the right.

Cheers,

Don

 

Thanks Don, I'll try to check tonight. I know that they were in the heelboard fuse panel as the kick plate was not fastened properly.

 

Guys- It was in fact a 5amp fuse in the heelboard behind the drivers seat. Put new fuse in and that activated the OBD II port.

Thank you.