I just had from what the Dealer told me new Software/Firmware uploaded into my 2009 Tahoe Hybrid. Operation seems to be smoother, it was already great with a decrease in MPG. Has anyone else heard of this?

 

I brought in my 08 tahoe hybrid last week for a once-over before the bumper to bumper expired. They told me they updated the firmware that supposedly provides improvements in driveability but we haven't noticed any significant change.

 

Ken, I'm not sure I want that decrease in MPG. How much smoother is it?

 

Its slightly smoother, however it was fine the way it was. MPG decrease is slight.

 

I received the new update last week (Friday) and promptly took a loongish
trip to see my folks after that (around 6oo miles round trip, mostly
highway). In the couple of days since coming back and settling back
into my normal driving (stop and go traffic, not much highway), I
have seen several change in the trucks' behavior:

- No longer do I get a "pregnant pause" when performing a full accelerate from a stop.
That almost got me in an accident once (tried to cross traffic and hit
the gas - almost didn't get out of the way)
- I can now accelerate a bit harder while staying in battery mode (and if
I push it a bit further, will go gas/electric). Have to push much further
to go totally gas (and then it comes back to dual mode pretty quick)
than I did before.
- When dropping from ICE to battery (at just under 30), the ICE used to
rev up almost an additional 1000 RPM first. Now it's much more subtle
(around 500-700 RPM).
- According to the "hybrid" screen, the truck stays in "hybrid mode" more
when driving around town. I will have to pay attention to the DIC to see
if it's v4 vs v8 any more differently than before.

Mileage on the trip was down and around town is down too (off by
about 2 MPG) but I am attributing some of that to the computer
being completely reset and having to relearn my driving habits.
The long road trip didn't help in that regard (not my normal miles).

Dealer had a devil of a time programming it, after all was done, the
airbag light was on and they had to get on the phone to GM to get
that cleared up. They said they received new programming
instructions earlier in the week about the procedure.

 

I have an 08 Tahoe Hybrid. I was averaging about 20.5 mpg, now I am down to 19.5 mpg after the update. Does it improve after a bit?