Cruise control sometimes over-revs engine on 2005 Outback

[Guest]

Just finished a 5000 km trip in a 2005 auto OBW with a lot of time on
freeways at 75 mph.

When using cruise control at high speeds (75-80 mph) and a moderate
hill is encountered forcing the auto to change down to 3rd, it often
then changes right down to 2nd immediately, with the result that the
engine screams right up to redline. Very disconcerting, not to
mention potentially damaging! I had to immediately get back into 3rd
by flicking to manual and changing up.

This only happens when in cruise control, not when in normal outo
mode.

Is this a fault or normal behaviour?

Apart from this one glitch I found the car an absolute dream for
touring, handling everything from freeways to high altitude dirt roads
safely and comfortably.

 

[CompUser]

Just finished a 5000 km trip in a 2005 auto OBW with a lot of time on
freeways at 75 mph.

It's an 05, take it back to dealership and get a
write-up, ASAP.

 

[Edward Hayes]

It doesn't sound as if it's working correctly. My 2000 does not do this. I
think if you run into dealer resistance you may suggest politely that it's a
safety issue for people and not just the engine. What if this happened on
wet or a sandy patch in the road??ed

 

[Skweezieweezie]

My 2002 LLBean H-6 does this under the same
circumstances, only it doesn't shift down past 3rd.

Since it wasn't a big issue, I never had it looked at
since other cars I've owned tended to downshift the
trans more during cruise control.

 

[Ron Joiner]

Just finished a 5000 km trip in a 2005 auto OBW with a lot of time on
freeways at 75 mph.

When using cruise control at high speeds (75-80 mph) and a moderate
hill is encountered forcing the auto to change down to 3rd, it often
then changes right down to 2nd immediately, with the result that the
engine screams right up to redline. Very disconcerting, not to
mention potentially damaging! I had to immediately get back into 3rd
by flicking to manual and changing up.

This only happens when in cruise control, not when in normal outo
mode.

Is this a fault or normal behaviour?

Apart from this one glitch I found the car an absolute dream for
touring, handling everything from freeways to high altitude dirt roads
safely and comfortably.

I have the same car. I don't encounter the problem tp the point that you
encounter but the 05 is a lot better going up hills than an 00 I had
previously. I also find the cruise somewhat sensitive to speed changes.
If your driving habits are such that you are fairly aggressive even at
low speeds the computer will, in a sense, learn your driving style and
adjust the shift points accordingly.

When going up moderate hills I either go into manual and stay in 3rd, or
switch off cruise entirely when going up steeper grades.

All that aside, it is a Subie engine and boxer engines are quite content
at high revs.

Ron

 

[FNO]

It doesn't sound as if it's working correctly. My 2000 does not do this. I
think if you run into dealer resistance you may suggest politely that it's a
safety issue for people and not just the engine. What if this happened on
wet or a sandy patch in the road??ed

You shouldn't be using cruise control on wet or slippery roads so the safety
issue won't help you. The cruise control on Subarus is very agressive.
However, if it is doing that on cruise, it usually means the car is down on
power for some reason. I would take it back and have them look at it and
why the car might not be at full power.

 

[Guest]

You shouldn't be using cruise control on wet or slippery roads so the safety
issue won't help you.

I wouldn't set CC on anthing else but freeways and similar roads in
good condition.

However, if it is doing that on cruise, it usually means the car is down on
power for some reason.

The car has plenty of power - better than I had ever expected for an
unblown 2.5L - so that's not the problem. It only happens at high
speed on hills just steep enough to make it change down to 3rd.

I think the problem must be either in the software or settings but
will be taking it to dealer next week anyway to see if they have any
answers.

Incidentally, I've seen several mentions here that the auto tranny
computer "learns" from the dirver's style but I haven't read anything
about that in the manual or in Subaru ads, so where does that info (or
Subaruan myth?) come from?

 

[FNO]

I wouldn't set CC on anthing else but freeways and similar roads in
good condition.


The car has plenty of power - better than I had ever expected for an
unblown 2.5L - so that's not the problem. It only happens at high
speed on hills just steep enough to make it change down to 3rd.

I think the problem must be either in the software or settings but
will be taking it to dealer next week anyway to see if they have any
answers.

Incidentally, I've seen several mentions here that the auto tranny
computer "learns" from the dirver's style but I haven't read anything
about that in the manual or in Subaru ads, so where does that info (or
Subaruan myth?) come from?

What I am implying is that you may have a little less power (paticularly,
torque) than you should, and the aggressive cruise control is causing the
transmission to drop two gears instead of one. If you are not on cruise
control, you would tend to be a little less aggressive with the gas pedal.
Generally, you don't see the cruise redlining the car; they aren't supposed
to be that aggressive.

As for the learning, I am not sure what they mean with the automatic. All
of them have adaptive ECUs and the ECU learns from the driver to optimize
ignition timing etc.; and that happens on both manual and automatic. I'm
not sure how the transmission would 'learn' anything; nor why it needs to.

 

[Danny Russell]

Just finished a 5000 km trip in a 2005 auto OBW with a lot of time on
freeways at 75 mph.

When using cruise control at high speeds (75-80 mph) and a moderate
hill is encountered forcing the auto to change down to 3rd, it often
then changes right down to 2nd immediately, with the result that the
engine screams right up to redline. Very disconcerting, not to
mention potentially damaging! I had to immediately get back into 3rd
by flicking to manual and changing up.

This only happens when in cruise control, not when in normal outo
mode.

Is this a fault or normal behaviour?

Apart from this one glitch I found the car an absolute dream for
touring, handling everything from freeways to high altitude dirt roads
safely and comfortably.

IMO, one area that Subaru has never gotten a good handle on is the auto-trans programming. In any
given year there seems to be glitches of one sort or another (i.e. shift-points, temperature-related
anomalies, and occasional bizzarre behaviour, etc.). -Danny

 

[Edward Hayes]

The TCM does learn from your driving style. It is reflected in the shift
points and speed of shifts. It is not immediately noticeable as it averages
so it takes several tanks of gas to make noticeable changes. I you wish to
reset the TMC & ECM to the default settings just disconnect the negative
battery terminal for 30 minutes or so and press the brake peddle several
times to assure all residual volter is bled off. Ed