Unable to talk to PCM via OBD-II

I have my carPC linked with my OBD-II hardware and software. It worked great for 6 months, and then stopped working a few months ago (no connection detected). I've tested the hardware and software by connecting to my moms 2002 Explorer and it works fine.

The engine hasn't been running well for a while and with the new transmission, it is much more pronounced. Once its warmed up and starts running closed loop and reaches 3k rpm it will alternate between very lean (lack of power, sometimes stalling) and rich every few seconds (according to my air/fuel gauge). I took out my Diablo chip, and have reset the computer multiple times.

I'd like to connect w/ the PCM and see what it's seeing/doing, but I can't figure out why it doesn't want to talk via the OBD-II port. My only thought is that the PCM has gone screwy. I took out my Diablo chip, and have reset the PCM multiple times w/ no luck.

check your fuses!!!!!! this happened to me on my 96 and it blew a fuse to the cigerette lighter if i remember right which also supplys power to the port for the scanner

It could be your PCM. I had to have mine replaced recently. Sometimes it was hard to start, other times the ignition kicked right in. I wasn't even able to program new keys or key fobs. Eventually one day I parked the X for 5 min and it wouldn't start again. The PCM had totally crashed and the security system went into default mode. The good news of the story, is that the PCM is covered under some extended warranty, so though my vehicle is 6 years old, I was still able to get EVERYTHING for free! I couldn't tell you for sure if you PCM is the problem, but if it is, you most likely can get a new one for free also.

You might want to test it with a different OBD scanner.

Good luck.....

cjbarron5 said:

check your fuses!!!!!! this happened to me on my 96 and it blew a fuse to the cigerette lighter if i remember right which also supplys power to the port for the scanner

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Thats probably it . . .I blew the cigarette lighter fuse a few months ago, and have yet to replace it since theres a power port in the center console. I'll check it later today. Seems like a strange place for the OBD port to get power from. . .but this IS Ford we're talking about.

That works much better. Now I just have to figure out whats wrong. . .

Thanks for the help.

cjbarron5 said:

cigerette lighter if i remember right which also supplys power to the port for the scanner

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Okay, now I have heard every thing !!!!!!!!!!!!!

The cigerette lighter ( cigar lighter according to the owners manual ) is probabally the LAST think I would want linked to my DLC.
Some Ford engineer who came up with that needs a swift kick in the tucas.

Ya just gotta love this board!!!

Glacier991 said:

Ya just gotta love this board!!!

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Indeed. I'd been trying to figure this out for weeks now. . . would have saved me a lot of headace to have posted this a week ago.