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Discussion Starter · #1 ·
We've noticed our 2019 Ascent with 36k miles revs up to 2500-3000 rpms at any slight incline and we are not trying to accelerate. Anyone else having this problem? Dealership can't find anything wrong with it, no warning lights on. had had all the updates done. Sounds like the transmission is slipping. Wondering if the 2020-2021 does the same thing? Was thinking about trading it but I don't want to have the same problem in a newer model.
 

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Sounds like the transmission is slipping.
By "Sounds like" do you mean it's making a horrible screeching sound, or do you mean it's revving up in inclines? The former is a CVT chain slipping. The latter is normal.
 

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Confirming that a '21 frequently revs from the current rpm to 3000rpm when pulling up inclines. It is like a smooth transition higher rev pull that is similar to a automatic transmission downshifting on the same incline. It's a cvt downshift. It feels like a hill helper. It feels like it is accelerating for you (and it is) and took some time to get used to. I am not a mechanic.
 

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I think this behavior (which is totally normal) is pretty odd. We have a lot of relatively short ups and downs near us, so I come across this a lot. If I hold my foot steady, then the engine speed will continually rise and rise and rise. The car will start gaining speed on its own and, even as I let off the throttle to try to keep the speed in check, the engine speed will continue to rise. Eventually, near the top of the hill, the engine speed will fall way back down to where it should be and then I lose momentum and have to get back into the throttle to keep a steady speed. I think it's kind of silly the way I have to keep working the throttle to try to correct the car's eagerness to modify my speed.

The loaner Outback and Forester I had did not do this. They'd climb the hill with a steady throttle and the CVT would initially increase the engine speed a little bit and then it'd...actually stay there! Speed up the hill was held steady, my foot was held steady, the engine did not race, and the cars drove like you'd expect them to.

I've found two ways to get around this in the Ascent. Either put it in manual mode so you can control the engine. Or ... as you climb the hill, keep crowding the throttle a little more as you progress. You'll likely speed up a little bit but the engine speed won't race if it's under load going up. It seems to race only if it senses speed decay as you climb the hill. I suspect Subaru did this for this very reason -- they didn't want you to have to call for more power with the throttle pedal if you needed it. I can appreciate that, but I think it's a very awkward implementation, and sort of a solution looking for a problem.

Nearly everything I don't like about how the Ascent drives is NOT present in the FB25-powered Outback and Forester (the weird throttle tip-in, the cold engine racing, the engine racing on hills, etc.). It really leaves me scratching my head as to why so many of these odd things (that are discussed all the time in this forum) were implemented in this car. I could understand it more if this is how all Subarus drive. You could chalk it up to "ah, that's just how Subaru does things." But it's not -- their other mainstream cars drive like any other mainstream car. The Ascent really stands alone with some of these driveability quirks.
 

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Nearly everything I don't like about how the Ascent drives is NOT present in the FB25-powered Outback and Forester (the weird throttle tip-in, the cold engine racing, the engine racing on hills, etc.). It really leaves me scratching my head as to why so many of these odd things (that are discussed all the time in this forum) were implemented in this car. I could understand it more if this is how all Subarus drive. You could chalk it up to "ah, that's just how Subaru does things." But it's not -- their other mainstream cars drive like any other mainstream car. The Ascent really stands alone with some of these driveability quirks.
Decently different transmission, no turbo, and both of those cars are a lot lighter. Whether or not they could have found a different way to accomplish the Ascent's needs, I don't know - but shifting, gear ratios, etc, are all different as well. Heck, even the FA24F/TR690 in the Outback is programmed decently different than the Ascent's FA24F/TR690, including having a different ratio range in the Ascent to accommodate the much greater weight.

I'm expecting programming refinements will eventually make its way into the Ascent line - your guess is as good as mine, as to whether or not early model years will benefit - Subaru has been known to do that from time to time (they've even done so with the Ascent already).
 

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Yep -- all good points. I'm hopeful that many of these driveability concerns can be fixed...and, once fixed, applied to earlier models. I totally acknowledge that this may be a long time coming. YouTube reviews of the Ascent note many of these things and Motor Trend noted the throttle quirk in their Outback review. I think some of this is often written up to "internet know-it-alls", but I think observations made here are pretty consistent with those made by very reputable automotive journalists as well. :cool:

I'm hopeful for some changes, to make these cars even more appealing.
 

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I get this also, I think it's kind of in a grey area and the algorithm doesn't know which ratio to dial in. It happens to me and is more noticeable at lower speeds but it happens going over pretty much any modest hill.
 

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By the way @Robert.Mauro it's easy to forget how heavy the Ascent is, just because of how light and easy it drives. I have to try to imagine how an Outback or Forester would drive if you hooked a 1,000 pound trailer behind it. The drivetrain would certainly behave differently than it does now. So maybe we I don't give the Ascent enough credit. :)
 

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We have a lot of relatively short ups and downs near us, so I come across this a lot. If I hold my foot steady, then the engine speed will continually rise and rise and rise. The car will start gaining speed on its own and, even as I let off the throttle to try to keep the speed in check, the engine speed will continue to rise. Eventually, near the top of the hill, the engine speed will fall way back down to where it should be and then I lose momentum and have to get back into the throttle to keep a steady speed.
It's flat where I live and haven't experienced or noticed this. I'm curious if you have done this with the throttle % info displayed. I'm wondering if the computer is really applying more throttle while your foot holds steady or if the fuel injectors are increasing flow or the turbo is getting less boost dumped. With all of the variables controlled by wire, I question how important foot position is. For example, even if you don't have cruise control engaged, if you hold your foot position constant, does the computer "think" that you want to maintain the same speed and attempt (badly) to accomplish that?
 

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The car will start gaining speed on its own and, even as I let off the throttle to try to keep the speed in check, the engine speed will continue to rise.
Yes it does and it is a weird feeling. I wish I could talk to the cvt and tell it there is a stop sign 100yards over the crest of that hill. On the other hand my pickup with a 6 speed on the same hill will bog down and several pedal adjustments are needed to make it shift and pull the hill. I love my cvt. I have learned to make the cvt do what I want it to do smoothly. 2250rpm is the sweet spot pulling away from a stop with no traffic. Doing this next to a suv in the lane next to me makes me smile, as I listen to their car shift through multiple gears losing a foot to mine each shift up to 55. Smooth and steady no faux shifts. Need to get going faster? 3000rpm with 1 smooth faux shift to 2200rpm. Above 3000rpms the faux shifts are noticeably quirky, I don't drive like that. Falling flat on it's face after a intersection with traffic? Keep it under 2000rpms and it wont do that. My truck does that if you don't run out 2ng gear enough. Every vehicle owned I have taken the time to make the tranny do what I want.

TLDR: I love my CVT
 

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TLDR: I love my CVT
I do, too. As much as I wish some of the programming was different, the CVT is one of the primary reasons I wanted to try an Ascent instead of a Pilot or Highlander or similar. Once you learn its quirks, it is possible to get a really smooth drive out of it.
 

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I'm curious if you have done this with the throttle % info displayed.
I almost always have the throttle % information displayed on the dash-top monitor, yes.

I'm wondering if the computer is really applying more throttle while your foot holds steady or if the fuel injectors are increasing flow or the turbo is getting less boost dumped.
The throttle % information is really an accelerator pedal position indicator...not an actual throttle butterfly position indicator. So it displays exactly what your foot is telling the computer to do...not what the engine is actually doing (note this when using cruise control: it'll always display 0%). You can see the actual butterfly position with various Bluetooth-enabled data loggers. I don't think I've watched various parameters under this specific scenario, but I do think that it's the CVT ratio that is changing, and not a significant change in throttle position or turbo boost or anything like that. I think it's adjusting the CVT ratio to let the engine spin up some to lower engine load and/or increase engine RPM to have the turbo ready to go if more power is suddenly called for (with your foot). I think I'd probably prefer the ratio change to be a little less severe (less intrusive to the driver) but if that's what Subaru is doing, then I can understand that.

For example, even if you don't have cruise control engaged, if you hold your foot position constant, does the computer "think" that you want to maintain the same speed and attempt (badly) to accomplish that?
I think this is what it's doing, yes. I think it's reading your steady foot as a request for steady speed and then trying to make the car do that. It ends up a little counter-intuitive, but I think that's what it's trying to do. In every other car on the road, if you don't add throttle going up a hill, you slow down. So you lean into the throttle for more power and you climb the hill. The throttle in our Ascents is rather sensitive, so you can't really lean into it too much, or you'll accelerate. So you end up holding it steady. But then the computer might sense your speed start to decay a little bit and it starts to increase engine speed through a ratio change (like a downshift). There's more power and torque there so you end up letting up on the throttle to keep your speed in check. And then you get into this really weird scenario where letting OFF the throttle seems to result in the engine increasing in speed. It's a very disconnected feeling and is very likely behind a lot of the "my CVT is slipping" complaints.
 

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I almost always have the throttle % information displayed on the dash-top monitor, yes.



The throttle % information is really an accelerator pedal position indicator...not an actual throttle butterfly position indicator. So it displays exactly what your foot is telling the computer to do...not what the engine is actually doing (note this when using cruise control: it'll always display 0%). You can see the actual butterfly position with various Bluetooth-enabled data loggers. I don't think I've watched various parameters under this specific scenario, but I do think that it's the CVT ratio that is changing, and not a significant change in throttle position or turbo boost or anything like that. I think it's adjusting the CVT ratio to let the engine spin up some to lower engine load and/or increase engine RPM to have the turbo ready to go if more power is suddenly called for (with your foot). I think I'd probably prefer the ratio change to be a little less severe (less intrusive to the driver) but if that's what Subaru is doing, then I can understand that.



I think this is what it's doing, yes. I think it's reading your steady foot as a request for steady speed and then trying to make the car do that. It ends up a little counter-intuitive, but I think that's what it's trying to do. In every other car on the road, if you don't add throttle going up a hill, you slow down. So you lean into the throttle for more power and you climb the hill. The throttle in our Ascents is rather sensitive, so you can't really lean into it too much, or you'll accelerate. So you end up holding it steady. But then the computer might sense your speed start to decay a little bit and it starts to increase engine speed through a ratio change (like a downshift). There's more power and torque there so you end up letting up on the throttle to keep your speed in check. And then you get into this really weird scenario where letting OFF the throttle seems to result in the engine increasing in speed. It's a very disconnected feeling and is very likely behind a lot of the "my CVT is slipping" complaints.
Around here, highway overpasses are about the only hills. Typically, I'll add 5 or so mph approaching the hill and then let off the gas letting momentum carry until the crest and then resume the throttle for the original speed on the descent. I've always done this for fuel efficiency since it doesn't take as much gas to increase speed before the hill as it does to increase throttle to maintain the speed up the hill. Haven't tried this in the Ascent yet.
 

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Discussion Starter · #15 ·
By "Sounds like" do you mean it's making a horrible screeching sound, or do you mean it's revving up in inclines? The former is a CVT chain slipping. The latter is normal.
No screeching sound, just sounds like the engine is going to blow up and the rpms rev. Really, really horrible to drive when trying to keep a steady speed going up mountain roads. I wanted to like this car but even my 15 yr old wonders what is wrong with it.
 

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No screeching sound, just sounds like the engine is going to blow up and the rpms rev. Really, really horrible to drive when trying to keep a steady speed going up mountain roads. I wanted to like this car but even my 15 yr old wonders what is wrong with it.
You said yours is a 2019 with 36k miles. Have you owned it since new? If so, what has changed (perhaps you moved to an area with more hills, etc.), or has it done this since it was new?
 

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No screeching sound, just sounds like the engine is going to blow up and the rpms rev. Really, really horrible to drive when trying to keep a steady speed going up mountain roads. I wanted to like this car but even my 15 yr old wonders what is wrong with it.
Ignore the sound/high rpms, and just drive. Don't try to adjust for it - just let it happen. It is normal for the Ascent to be in the RPM range you described when it is climbing a hill. It's a pretty heavy car.

Using manual mode to enforce a lower gear can make the engine lug, which can damage things.
 

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Discussion Starter · #18 ·
You said yours is a 2019 with 36k miles. Have you owned it since new? If so, what has changed (perhaps you moved to an area with more hills, etc.), or has it done this since it was new?
No, we have just had it about 5 months, bought it with 31k miles. Didn't do it initially, just started about 3 months ago. No changes, same roads.
 

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Interesting that it didn't do it before - it should have. Did you have any recalls or reprogramming performed since you owned it? That may have changed the behavior.
 

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Discussion Starter · #20 ·
Ignore the sound/high rpms, and just drive. Don't try to adjust for it - just let it happen. It is normal for the Ascent to be in the RPM range you described when it is climbing a hill. It's a pretty heavy car.

Using manual mode to enforce a lower gear can make the engine lug, which can damage things.
Haven't tried it in manual mode. I guess I can learn to live with it if I know that it's a "normal"CVT thing. It's just really bothersome sometimes; don't understand how that could be normal for any car.
 
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