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Loss of power

Model Years 2018 to 2023 
54K views 203 replies 59 participants last post by  Turnoble 
#1 ·
Hi all, Bought a 2019 Crosstrek 6 speed last October 2018. After about a month while driving. Noticed a sudden and dramatic loss of engine power. This went on for 10-15 minutes. Odd thing is that while it lost power. It was still running smoothly. it has done this 5 times in the last year. NO CEL.
It has done this on flat terrain at 70 degrees. In the rain at 62 degrees. Pulling a 4-5% grade in 97 degrees. Tank almost empty as well as after just filling up.
So far Subaru has said. Unless there is a fault code, We can't do anything. Then they had a the gall to say: Just drive until it breaks.
This is BS. We do a lot of traveling in our coach and tow the Subaru behind it.
Total miles on the car in the last year is 8,000 as I do not like it at all and drive our 2003 Legacy Wagon as it has better power and drives better as well.
 
#2 ·
I believe I have the same issue as you. I dont experience a dramatic loss of power but the car does seem to bog down a bit usually in 2nd and 3rd gear around 2500 RPM and tends to clear up right at 3000 RPM. Im just under 8000 miles with a 2019 6MT. Ive heard of others experiencing the same issue on the Crosstrek FB page. I took the car into the dealership today, they couldn't really replicate it but did reset the ECU. So far it seems okay but maybe others can chime in?
 
#3 ·
I suspect that it is one of two things.
1, A software issue. But it seems odd that it would have happened just 5 times in 8K miles. And under such variable conditions.

2, A sensor issue. Perhaps the O2 exhaust sensor is out of range on the voltage it sends to the fuel injection. But not enough out of voltage range to log a fault.

As it's so intermittent. It's always a tough one. And truth be told. The mechanics these days have about ZERO diagnostic skill. If the computer doesn't say there is an issue, Then the modern mechanic will just parrot that there is no issue.
 
#13 ·
I think Subaru must have farmed-out some of software issues to the Boeing folks who helped certify the B-737 Max. Well, not quite that bad, but you get the drift. I've been feeding my 2015 Forester premium fuel since about a year after I got it.... great engines, but need some TLC>
 
#4 ·
I have a CVT and one time by accident had it in M mode (for using the paddle shifters). For a minute, I wondered what was wrong, that it seemed to bog down at lower rpm. I quickly noticed my problem and moved the shift lever over to the right (auto), and the CVT immediately found the proper rpm for the acceleration demand I was giving it with the throttle. It took off normally after that. Seems this engine doesn't like a lot of throttle at low rpm (in manual mode).
 
#5 ·
Big difference though from yours. When I'm driving at 45-50 and need to downshift twice and keep my foot nearly to the floor to keep it at 35. That's an issue.

Even on flat terrain when I was doing 60MPH in 5th. It took a long, long time to even gain 2 MPH. That's a serious issue.

And too think I gave up a 2014 Mercedes 2 liter twin turbo Diesel AWD & 40-45MPG for this POS. All Because the Mercedes couldn't be flat towed and I got tired of having to load it on a trailer. And I have heard so much about the alleged Subaru goodness. I wish I had the GLK back.
 
#7 ·
Good call. I'll ask the dealer to check that out.
TPS and an electronic throttle pedal are essentially the same thing but in different locations. Just potentiometers. My 1998 motor coach has an electronic pedal as the 11 liter Cummings is 30 feet behind my steering wheel.
 
#8 ·
one way to check (be sure traffic is clear) when this problem arises is to throw it in neutral and see if it revs up like normal. I'm not sure the computer diagnostic stuff the dealer does would detect it unless it was currently having the issue.
 
#9 ·
That's the trouble with the ECU's and their programing/diagnostics. It might not be in total failure (yet) and just doesn't meet the programed threshold of throwing a code. That's why I thought it could be the O2 sensor. It could be sending the wrong voltage rather than just not sending voltage like if it just stops working.

Most TPS and APP's will throw a fault if they stop working. But what about when they are still working and just sending the wrong voltage.

I'd say your correct on the dealer not seeing it until it's coded or happening while on a test drive. But with this issue coming up on average of every 1600 miles. It's just a shot in the dark for this to come up during a technician test drive.
 
#10 ·
Same thing here. 2019 Crosstrek Premium 6MT. Loss of power when shifting to 3rd or 4th. Took it to the dealership and was told to switch to premium gas and to consistently run the car until the low fuel light came on (which I find odd).

I am also randomly experiencing engine knock in the middle of the summer, which is unusual.
 
#12 ·
Engine knock in an engine that is fueled with the factory recommended grade has got to be a software (ignition advance) issue. Premium might help. But that's like taking care of a broken leg by taking opioids and not having it set and a cast put on. The pain may go away, But the cause of the pain is still there.
 
#15 ·
I have data logs of this phenomenon. The ECU pulls a TON of timing and the MAF signal goes nuts. I'm satisfied that this is an ECU / software issue. This issue has never re-occured since I flashed an aftermarket map. If any of you experiencing this have the ability to data log it, it would probably go a long way in getting actual attention from Subaru. A brand new car falling on it's face at 2500rpm is not 'Normal'.
 
#19 ·
Glad I stumbled across this thread.

I have the same symptoms that you all describe on my 2019 6MT.
It will bog/fall on its face around 2500 rpms, and act like it wont take throttle input. At times, will barely accelerate without downshifting to get the revs up over 3000. Worse with the A/C on. Seems to be heat related, at least in my case, as around town driving, especially in the summer heat seems to cause it.
I have a Scan Gauge, and while I can't data log, I can see that it will pull huge amounts of timing when this happens - like 8-10 degrees compared to when it's not "acting up". Fuel grade makes no difference, which makes me think it's not knock sensor signal related, whether it's 87 octane (E10), or non-ethanol premium (91-93). I do occasionally get spark knock, but that clears up with the higher grade fuel. But the bog does not.

Has anyone gotten anywhere with a dealer actually investigating the issue? Mine blew me off like I didn't realize that having the A/C on will rob some power from the engine. Yeah, no kidding...I'm a master certified tech on 2-wheels, but don't want to go the aftermarket calibration route for warranty reasons.
Just had the ECM reflash completed for the ignition coil recall - we'll see if they snuck some other updates in there to clear this up.
 
#20 · (Edited)
I would be very curious to see if Subaru did address this with the reflash. I'm in a bit of a tight spot myself, in that I would like to get the warranty reflash to address the ignition coil issue, but I don't want to go back to the stock map. I also don't really want somebody going poke around looking at my flash count if I bring it in. I'd REALLY like to know exactly how common the coil issue is and what exactly is going on, but I doubt that info will ever come out. I'll probably just assume I don't have a problem and skip the warranty flash.

If it does not clear up with the reflash, I was able to regularly and reliably replicate the bog on a long hill in a 45mph zone. 4th gear around 2600 or so put it right around the speed limit and with enough throttle to put it right in the middle of the bog. Maybe you can find a similar stretch of road to repeatably induce it and get them to ride along?

But, I'm sure somebody will be along shortly to tell us that it's all completely normal, that it's the CVT acting at a distance on our 6MT cars, or that you need to run it up to 6000rpm to climb a gentle hill, and ask again if you had the AC on.... lol

Please let us know what you find!
 
#21 ·
Please let us know what you find!
Bummed to report that the "bog" is still there.
Same behavior with the timing as before the reflash.
I finally had a chance today, with temps over 50 degrees, to do enough around town driving to induce this again - repeatedly. :mad:
I'm really curious how much those that have experienced this have pressed it with their local dealer/Subaru.
Any input would be appreciated, because at times when I'm not anticipating it and really jumping hard on the throttle, it can be borderline dangerous.
 
#24 ·
I have the 6spd MT as well on my 2019 Premium. I have not experienced this issue, but I have experienced this in other MT vehicles I have owned, and it was always the clutch wearing out. This sounds unlikely given the very low mileage of your vehicle but it may be something to suggest to your mechanic. Also, doesn't the new ECM/Ignition Coil recall notification mention the loss of power if the short circuit of the coil occurs while the vehicle is in motion?
 
#25 ·
I don't believe it's a clutch issue. I know where you're coming from, however I've experienced this since 5000 miles, and now with about 25000 miles, it has not gotten better or worse.
Coupling that with showing the timing advance going from about 5 degrees to -7 degrees when this happens tells me it's likely ECM calibration related - whether it's a byproduct or the root cause.
 
#26 ·
I did mention this thread to my dealer when I took my '19 in for the coil recall, but they were unaware of any issues. In thinking back to this summer, I do remember my car being sluggish accelerating from a stop light on an incline. But that was only in 1st and 2nd gear. I attributed it to the "hill assist" feature that automatically applies the brake for a couple seconds to prevent a backward drift for folks not comfortable with manual transmissions. I wonder if symptoms go away if you turn off the "hill assist" feature? If you try that can you update the thread with your findings?
 
#29 ·
I my name is August and I am 6 Spdn MT coil recall power victim too. Below is a paste of a thread I started:

Took my 2019 6 speed MT XV premium (7 months old and 2800 miles) in for the coil recall and the first oil change (figured it is cheap insurance for my warranty). There is now a super noticeable hesitation on acceleration and lurching after the hesitation, after today's service. The XV is also loosing pep when driving uphill.
An odd note, my gas went from 11/12 before the service to 12/12 after.
Does the car need to relearn my driving style, or is something else going on, trip miles didn't change or anything?

P.S.
I put in my K&N Filter and started noticing some lag. After researching this forum and reading a couple threads about this issue, I cleaned my MAF sensor because maybe filter oil, and everything was jimdandy! I'll try that again tomorrow.

Note:It seems better when the A/C is off (I live in FL). Other things I noted: Once I get above above 2500RPM, the issue goes away, and if I stay above, it's all good. Also, my original black filter was replaced with a blue one.
 
#30 ·
Seems most issue here is timing related issue, it can be knock sensor or it is the way ECM programmed to protect engine with high compression ratio. I find the ECU is quite complex since I find the engine quite sensitive even though you use high octane fuel and the timing tune can be very aggressive, so I belive the issue is more lack of fine tuning coming from factory
 
#31 ·
There's more on this topic in this thread. Model Year 2018 and Newer - Hesitation while modest accelerating
I have driven a little over 700 miles now since having the PCV valve replaced under the recall and have not detected my previous problems yet. The bad PCV valve has a pink ring on it and has an aluminum housing, the new one has a blue ring and is steel. The PCV is visible looking in from the right side. The air intake splits and goes to the left and right sides of the engine. There's a split in the plastic housing going to the head. Shine a light in between and you can see the valve. I have a 2018 MT. My fingers are still crossed, I'm hoping mine was leaking in early stages before complete failure when the internal parts fall into the engine.
 
#35 ·
Here's the recall for the PCV. Check for Recalls: Vehicle, Car Seat, Tire, Equipment You can also download the recall instruction from here. Apparently there is a washer that is free to move inside the PCV. My assumption is it can eventually wear through the aluminum housing allowing the 4 internal parts to fall into the engine. Hence, the new valve is steel.

It's only my hopeful theory that as it wears out it might allow enough separation to allow the valve to begin to leak. This is more comforting right now than to think as the season begins to heat up in April I'll be faced with sucky performance again.
 
#39 ·
As Zbroussard stated,there were definitely knocking signals in the data log.Your engine wasn't really knocking.It was a false alarm being sent by the knock sensor which caused the ECU to retard the ignition timing.Because the sensor was just sending bad data and the sensor hadn't actually failed,no fault codes were reported.If the dealer refuses to change the sensor because there are no fault codes to verify it's bad then take it to someone who will change it and take the bill back to the dealer for reimbursement.
 
#40 ·
Latest update, So far I haven't had the loss of power return. But alas. It's going to be hard to tell if it was fixed as it was an intermittent issue anyway. No matter though, As long as it doesn't return. I'll be satisfied. As more time passes without the issue returning. Then I guess I/we have an answer.

As to the issue of having the knock sensor replaced right after the coil pack re-flash. I'm not worried as long as the problem goes away. I do have a problem case number at Subaru Corporate. So will continue to talk with them.

Preaching to the choir on this forum will not cause nor help Subaru to fix an issue they aren't aware of. So please do call Subaru America HQ and open a problem ticket if you have this problem.
 
#41 ·
One of the posts said something about getting a full tank of premium to help with this issue. I have been using premium for the past two or three fill-up (usually at half a tank). Not sure if it the cool weather or the premium fuel, but the bogging seems to be diminishing. Accelerated, in third, with both the A/C on and not, up fairly steep (for Florida) hills and no need to floor it just to maintain speed.
Is this issue working itself out for anyone else?
P.S. My dealer knew nothing about this issue.
 
#42 · (Edited)
The official fuel requirement per Subaru is regular unleaded. If folks want to buy premium to try and MASK an issue, That's up to them.

When the ignition timing goes from it's normal advance setting to retardation. That is an issue that will not work itself out.

My dealer didn't know about it either. That is why you need to call Subaru Corp and open a case number. If enough do so. Subaru will have to solve the issue.
 
#43 ·
The official fuel requirement per Subaru is regular unleaded. If folks want to buy premium to try and MASK an issue, That's up to them.

When the ignition timing goes from it's normal advance setting to retardation. That is an issue that will not work itself out.

My dealer didn't know about it either. That is why you need to call Subaru Corp and open a case number. If enough do so. Subaru will have to solve the issue.
What I was going for, is that not use premium for the life of the car, but run a tank or two of premium to clear the cobwebs, then switch back to regular with the hope that all is better. I would like that number, I did email Subaru, but a call is better.
 
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