2009 Sonata & Cruise Control Auto Trans Problem

2009 Sonata w/i4 Engine & Automatic Transmission problem when using
Cruise:

Problem: The car will not stay in 5th gear with the torque converter
locked up when encountering the slightest incline while the cruise
control is activated. Instead, the car will 5-4 shift, unlock the
converter, go awhile, do a 4-5 shift, then do a 5-4 shift, so on and
so forth. This is an undesired operation of the engine/transmission
ONLY while the cruise control is activated. This has happen on eight
of the 2009 Sonata's I have experimented with.

If the cruise control is OFF and you are just using the gas pedal, the
trans will stay in 5th gear, and the torque converter will stay
locked, on even bigger hills, and you can even accellerate gently
without the transmission doing a downshift. This is the desired
operation of the engine/trans that should also happen when the cruise
control is enabled.

I have asked the dealer to fix this problem so the the cruise control
operation of the transmission/engine will more closely pattern itself
to non-cruise control operation. They say that they cannot because
Hyundai USA has not released a software upgrade to fix the problem
even though the vehicle is a one model year old and the 2010's are
programed the same.

If this is happening to you, find it irritating and fuel inefficient,
and you would like it fixed, I encourage you to inform your dealer and
to call Hyundai USA customer service at 800-633-5151 and make your
wishes known. (Their phone number & address are at http://www.hyundaiusa.com
located under the "about Hyundai Tab" - "Contact us"). I have already
made their engineering dept well aware of this problem.

 

My 2008 Elantra does the same thing. I assume that it is the cruise
control's effort to maintain the set speed.


---MIKE---

 

My 2009 V6 did "busy shifting" with/without cruise on slight hills. Car
was an early production model. Had dealer do a TCM Calibration Update
(TSB 09-AT-005) and that improved the situation. Have dealer check to
see if you need to have that update.

Larry

 

Just checked the TSB. It was for the V6 only. Sorry for the
misinformation.

Larry

 

On Fri, 11 Sep 2009 11:42:08 -0700 (PDT), Sjtcar

I found the solution was to move the auto shifter to the right when
you were at the correct speed and gear. This way the trans will not
shift up/down until the shifter is returned to the left (or you
manually shift down/up by using the shift-o-matic (don't have my
manual in front of me so I think it is called this).

 

On Fri, 11 Sep 2009 11:42:08 -0700 (PDT), Sjtcar

I found this irritating also. It was suggested (and it works rather
well) to move the auto stick to the right. When in this position the
trans will not shift up or down until the shifter is moved back to the
left.

 

"move the auto stick to the right"

Do you mean shift into a lower gear?

 

I don't know about the 4, but on the 6 the transmission goes into manual
mode by pushing the stick to the right. It will only up or down shift if
the speed is far out of tolerance, like first gear at 5000 RPM

 

Oh yeah that's right, I recall that now. Well the Mrs drives the thing
99.9% of the time - it's hers. I'm happy driving my GMC Sierra.

 

This is not so much a solution as an intermediate workaround. The
torque converter will still unlock using the "Sportmatic" method of
locking into 5th gear. Also, by defination, the cruise control is not
working correctly according to page 94 of the owners manual. This is
why I would like Hyundai to issue a software upgrade that would make
the cruise control operation mirror the non- cruise control operation
of the engine/transmission shifting pattern.

 

No. Moving the stick to the right puts the auto trans into the manual
gate mode (see page 9 of the manual - Sports Mode) where you can
manually shift up or down (with some limits).

 

Indeed, the way you describe the issue makes it seem like the cruise
control is operating as programmed. Without any programming changes
being released by Hyundai, there's little any dealer can do to change
this. In that sense, you're on the right track to achieving a
resolution to the issue. Whether Hyundai issues a change depends on
whether the engineers believe that making the change will adversely
affect the cruise operation and whether Hyundai believes the benefits
of the change outweigh the consequences.

I don't recall any cruise complaints on this model, so I haven't been
experimenting with it's operation. At what speed(s) does this issue
occur?

On the other hand, I just read the cruise control portion of section
one owner's manual and fail to see what part of the description is in
disagreement with the manner of operation you describe. Can you point
me more specifically to which portion of the description you feel the
operation fails to satisfy?