KAP 140 trouble

The B/K KAP 140 autopilot in my 2006 Cessna T-182T has a problem that is
baffling the avionics shop. The altitude capture/hold function does not work.
Here are the symptoms:

o All other functions work, including +/- vertical speed control.

o It will accept and correctly execute a vertical speed setting, but will
fly right through the target altitude.

o If Altitude Hold is engaged in level flight, it will not maintain
altitude.

o If Vertical Speed is engaged in level flight and set to "0", it will do
a fair job of maintaining altitude.

o According to the tech, the KAP 140 perpetually believes it is at 13,000
ft, and nothing will convince it otherwise. The unit has its own barometric
setting, independent of the G1000. However, the latest theory at the shop is
that it is a Garmin problem.


The tech's have spent a lot of time on the phone with Garmin and B/K,
listening to a lot of finger-pointing back and forth. They currently have
over 20 hours labor charged to the job--thank goodness it's warranty. I'm
able to fly the plane this weekend, but it goes back in the shop Monday.

Anybody have any ideas?

--
Dan

"You spend money to buy aggravation."
-Chinese proverb