OBD II, vehicle won't communicate?

[iamthedemoman]

So I went to start my 2000 7.3 yesterday and it started right away, except two seconds later it went into what seemed a limp mode. It ran the same way when the injector went out a while back. The engine light comes on and there's no power. I changed out the fuel filter and put some fuel treatment in and it ran normal, but then did the same thing running down the road. I'll stop and it will run fine, but when I go through the gears it goes into limp mode until I stop and wait a minute or two.

So I used a Snap On OBD II scanner on both the general setting and the vin for the truck and it won't read because I'm told the vehicle is not communicating with the scanner. I thought maybe the chip was interfering so I took it out, but still the same problem. Last time I used the Snap On scanner it worked great. All the fuses are good. I'm stumped. Any ideas?

[sldghamr]

sssooo, no codes??
you might have clogged injectors, try some cleaner if you can get the enginge to run long enough.

your CPS might be bad.

[iamthedemoman]

I've got an extre CPS. I might swap it quik just for the heck of it. I've also got some cleaner. I'll throw some in and let it run a while. It idles just fine, until I get on it.

[Cypher]

i don't see how a bad CPS would cause it not to communicate with the scanner. I've used the modius and snap on scan tools on these trucks and never had a problem.

I'd almost want to say maybe theres a problem in a PCM but these days thats a very rare thing.

[lilredpowerstroke]

Youre 100% sure that all the fuses are fine?? Sounds like a blown fuse for the OBDII connector to me.

[grabowskimech]

Yeah, I would recheck the fuse to the obdII connector or also check the connector wires themselves, guys sometimes like to accidentally kick out the wires.

[iamthedemoman]

Changed CPS, that's not it. Checked fused a fourth time, and they're all good. All the connections there and good for OBD II. Maybe I'll try a different scanner because there is no change.

[WEWILLE]

I would try a different scanner, if that doesnt work you will need to get into some indepth troubleshooting. You should also check all the powers and grounds gowing into the pcm, and the continuity from the pcm to the dlc.