Hey ya'll

So I went to get the Jeep smogged a few weeks back and the tech says as soon as he plugs in the computer the 2005 Libby dies and the dash reads "No Bus". It has been running fine without incident, so I plug in my scan tool and it's dead, as in no power or numbers on the tool, guages on the dash all die, "no bus" comes on, and the check engine light dings on. As soon as I unplug it, everything is back to normal, guages, check engine, everything. I read up about the dielectric grease and pounding the dash and I feel like I've exhausted every forum and search engine and my problem seems somewhat unique. I tore the dash apart today, there's only one plug in the back of the instrument cluster and I applied some dielectric grease but still getting the same problem. Does anyone have any ideas? I've paid DMV but I don't have a sticker and I don't know how long they will give me until I pay penalties. I pulled every single fuse on the interior panel, all fine. I really don't want to take it to the dealer.

I did try the "pound on the dash" thing and after beating my meat hook to a pulp it powered on the tool so I drove it to the smog shop. By the time I arrived...the same problem had returned. Any ideas? The dash is torn apart right now awaiting fix and reassembly (or gasoline and match).

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2005 4x4 KJ

Sounds like a loose wire connection somewhere between the PCM and OBD port.

You will probably need the KJ service manual and a good voltmeter.
The fact that your scan does not power up when plugged in is a clue that either there is no 12v signal at the OBD port or there is a bad ground connection.

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U.S. Army Retired

Gotcha, thank you for the response. I will search how to kind the KJ service manual and try to dig out my voltmeter. I read that people experience the no bus problem frequently but mostly what I read stated their Jeeps would either not run at all or the dash guages would completely fail, whereas mine do none of that with a scanner unplugged but all of that with a scanner plugged in. I'll see what I can do and report back. Thanks.

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2005 4x4 KJ

Well I ripped the dash apart and was getting nowhere. I found the KJ Factory Service Manual online and started tracing things around. I left my scantool plugged in with "nobus" on the dash. I went to the PCM on the drivers inside fender in the engine compartment, took all the plugs and tried to push them up into the PCM. "Ding!" I go inside the cab and the scantool is powered up and the check engine light off. I left the scantool plugged in for the remainder of the day and then the next on my way to get it smogged and it stayed powered up the whole time. It passed smog quickly and I was on my way. Thanks for the input.

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2005 4x4 KJ