Most likely, you have a software issue that can be updated.
You might want to have it checked and see if there are any
updates available for the ATC module. There are 3 tsbs that
can related to the 4x4...one for crow hopping when in auto 4hi,
this addressed with software updates and a new encoder motor
sensor, another for 4wd lamps inoperative, or weird shifting things
happening, again software updates for this, and the last is for a
dash switch problem, which now that I look at it, may be your problem,
it says that the shift ranges can indicate that you are in another range
when you are not. Fix is to replace the dash switch if you find the
B2725 code. I think that you should definitely take it in, get it scanned
for that code, and then have any software updates applied.
Also, do you have any idea on the dates of the software upgrades? When we
took it in 6 months ago, all the updates were done when they changed the
clutch fan. One of the updates did take care of the stalling problem it had
at idle after it was warmed up. I just love the modern age:-)
The fact that you had it in the shop and some updates were done
doesn't always mean that they updated the ATC module. Each
module has to be updated individually, and I know that in our
dealership, we do not just do "all" the updates as a routine
thing. If it has the stalling problem, it would most likely get
an update for the ECM/PCM module. Unless you were
complaining about any problems with the Auto Transfer
Case, I would doubt that any update was done to the ATC
I had an Avalanche in the other day, ATC problems, and
dash gauges would intermittently not work. Both problems
were addressed by software updates, each update had to
be done individually...in other words, I have to request info
from the vehicle, take the scan tool to the computer, check
and see what (if any) updates are available for the ATC module,
and the IPC module. Then I picked one, downloaded "that"
piece of software, and go back to the vehicle to reflash "that"
module. Then repeat the whole process again for the other
module. I'll be glad when GM figures out how to simply update
all the modules at once. Because I'm paid only for what the
complaint lines are, I don't spend any time looking through all
the other modules to see what updates might be available. GM
is not really interested in us doing that sort of thing. Just fix what
ails it, sir...and that's it.
If you are paying for the updates yourself....then I'd be tempted
to ask the tech to go through and check each module, but just
remember that this process is time consuming...especially if you
reflash more then one module. GM pays 24 minutes to reflash
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