wrangler, airbag , check engine light and no bus

Your pci bus is either failing (the bus originates from the BCM), or one of the modules that usues the bus is dragging that bus down (shorting it out). (PCI bus is the single-wire bus over which all the various modules of the vehicle communicate - if it fails you see exactly what you are seeing.)

You have a Wrangler (though you don't say what year), but I know from reading the LH car forums (LH cars have similar bus and module design), when this problem occurs (with the "no bus" message in the odometer window), the problem generally ends up being a bad TCM. You can either pay to have it troubleshot (no guarantee that they'll nail it due to it being intermittent - but you'll still pay a bunch of money), or take a small gamble and get a TCM (the right one to work with your vehicle) from a junk yard for under $50 and have a very good chance of that fixing it (if it doesn't, you're only out $50). Plus *IF* the dealer by some miracle pinpoints it, they will charge you *several* *hundred* dollars for a replacement TCM (*plus* the diagnostic time)

I got a $6000 Concorde for $1000 last year because it had this exact problem and the used car lot spent (wasted) all kinds of money at the dealer testing and replacing this and that with no success. The problem went solid for a couple of days, allowing me to pinpoint it to the TCM (plus, as I said, the LH car forums kind of led me in that direction). Got a TCM from a junk yard - no problems since. Four hours plus $50 for the part invested.

To locate a TCM for your vehicle, use the drill down at

You can narrow the search to state or region to keep shipping time to a minimum, but even if they have to ship from 7 states away, so what. You'll probably find several listed in your state or an adjacent state - like I said - for under $50 (after you drill down with vehicle and part, start by clicking on the page with the asterisk, and work your way backwards to find the best price).

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

Some Wranglers had cluster connector issues that cause problems like you're having. Look for TSBs for your vehicle.