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hooziewhatsit 04-03-2005 03:28 PM

Cruise control surges/jerks downhill
Hey all,

I'm posting this on behalf of my grandparents. A while back they replaced their 98 legacy with an 05 legacy.

Immediately, they noticed a problem with the cruise control. Going down hills, the car surges/jerks while trying to maintain the correct speed. My grandpa thinks it's related to the new fly by wire system, and the systems are having trouble communicating.

They have taken the car to the dealer many times and have come to the conclusion that:
- Every similar car they drive has this problem
- No one else has complained about it, so it 'is not a problem'

They've gone to the factory with their problem and around March 20th got the following response.

Basically, what they are experiencing is a 'normal operating characteristic of the car.' The cruise control was only designed to work on FLAT, straight, level roads, not uphill or downhill. They also said they have duplicated this on other models, and since no one else has complained, it is not a problem in their eyes.

They also say to check the owners manual about the dangers of using cruise during inclement weather, lol.

If anyone else is having this problem, my grandparents advise going straight to the factory website to get all the problems reported in one place. Hopefully this way something will get done about it (if there turns out to be a true problem). If you want to email them about it, the address they used was

So any comments? questions? Most of the cruise control problems I've found on this site relate to it shutting off after overheating.

Thanks a bunch.

fbi012 04-03-2005 03:35 PM

well I noticed this happening to me as well, but I dont think its a problem.
I have an A/T. this happens when I set speed at about 100km/h, which is where the car shifts gear, so as a result it studders abit. thats my guess. I dont mind reporting a problem but probably they wont mind me since im in canada?!

hooziewhatsit 04-03-2005 03:36 PM

lol, oh yea, I guess I should mention that they have the manual tranny, non-turbo, not sure about the specific model though.

edit: and every other car they've driven, including their previous subarus, have not had this problem.

tytek 04-03-2005 07:23 PM

funny you say that. i was going to ask about the same thing. my 05 l-gt 5spd surges/jerks when going downhill on cruise control (10k miles). a loaner non-gt 5eat had this "problem" also (6k miles). i was wondering if it was due to the electronic throttle, but, my 04 forester xt 5spd (25k miles) did not suffer from this condition. i have AP stg 1 now and it still does it. does anyone know why it feels so rough?

RoundBoy 04-04-2005 07:00 AM

wait.. manual using CC ? I would imagine that the engine is bogging while going uphill (depends on the grade) because its expecting a downshift?

In an auto car.. the car would do a 4->3->4 shift if needed...

whereas the car is 'stuck' in a particular gear in a manual.

eamiller 04-04-2005 07:18 AM

Since I live in "flatland" northern Indiana, I haven't seen this issue when the cruise is trying to maintain a steady speed.. However, I have noticed if the cruise is set and I want to "tap up" a few miles an hour that it will surge if I hit "accel" to rapidly... If I tap "accel" with a longer pause in between taps, it doesn't do it.

vern 04-04-2005 07:46 AM

I use the cruize in my GT all the time on the highway. I set it at about 75 and go... uphill/downhill never noticed this symptom. At this speed the rpms are in the sweet spot for power and she flys up the hills no problem and coasts down the other side with no ill effects.

Does it happen as the car is exceeding the set speed due to steep grade? Or just trying to maintain the set speed?

As eamiller says, the power will surge on if you hold the accel stick or tap it rapidly.

Sean05 04-04-2005 10:15 AM

I currently own both a 05 Outback XT and an 05 Legacy 2.5I, and strangely enough only the 2.5I has the problem with surging going downhill. It only happens on relatively steep hills where the car will accelerate with no throttle input. The Outback acts like nothing happens while the Legacy seems to take the "stab and release" approach. I might take the Legacy in to the dealer soon, but the Outback has to go in first, the brakes on that thing suck.

icehousewvu 04-04-2005 10:45 AM

Yep, this happens my car ALOT... There are lots of hills and mountains here so I experience it quite a bit. 2.5i 5MT


hooziewhatsit 04-04-2005 11:39 PM

thanks for all the replies/confirmations of the problem. I'm also curious if you've had this problem personally in other cars.

anywho, I just got back an email from them with some more information.

They see it on gentle declines to much steeper declines. By gentle decline, they mentioned a local road that drops *maybe* 100 feet over a mile for a while - ie, not very steep.

They don't have any problem with it maintaining the correct speed going uphill, even on steeper roads.

agctr 04-04-2005 11:41 PM

Are you sure your not talking about the engine braking that occurs when you have the Cruise Control ON. It happens in most vehicles as its the system trying to maintain the speed which you have set.

gtguy 04-05-2005 05:43 AM

Moved to "Warranty Issues and Problems."



gmorgan1387 05-31-2005 04:43 AM

cruise control
I just bought a 2005 legacy 4 cylinder 4 speed automatic
and the cruise seems to be bucking when i go down hills.

It is amazing that after driving other vechicles on the dealers lot that has the same problem that more people have not complained to Subaru or if they did Subaru is not responding.

We current own a 1997 & 2002 that do not have this problem.

Where do you go to get someone, other than customer service, at Subaru to fix this?

I can't image that customer service is telling us that cruise is only for flat groudn; what a bunch of bull............every other vechile we have (ford) cruise works both on flat land and hills.

They really need to respond to this issue.

We have stopped driving our vechile until they resolve this issue.

fbi012 05-31-2005 09:26 AM

call SOA, thats my best guess
and I did complain here but Im not sure if Subaru Canada reports things to SOA.

NutBucket 05-31-2005 10:29 AM

Seems to work fine for me. I tried it going through the Sepulveda Pass for the SoCal folks. Set it as I merged onto the 405 south from the 101 north/west and canceled it about when I got to Wilshire.

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