Jump to content

Anyone know expeced RPMs under load?

Recommended Posts

For a while now our CVT 2011 Legacy has been stumbling (feels like it) at stop signs and red lights. Yeah, the Torque Converter thing, likely. Yesterday it died on me (first time this happened to me).


I know the warranty for this was extended.


I think dealer will give me hard time though unless actually reproducible. But it does not reproduce frequently, but it DOES stumble and "almost die" (vibration included) very frequently when driving in subdivisions.


So I plugged in my OBD2 thingamajig and took some logs using my phone. I see that when the problem happens, the RPM range drops to ~500 and when it does not, it is ~700. I plotted the vehicle speed with engine RPM and this is what you see here.


Now - anyone know if it is documented what the engine RPMs should be under load? Shop manual seems to indicate that:


Idle speed at Park or Neutral position (rpm): 675 (CVT)


But that does not tell me what is expected under load? Is this even something that can help me make the case?




The lowest recorded values (in RPM) as the car was coming to a full stop were:










On the right side of the graph, you can see how the RPMs stay around 600-750 range even if the vehicle stops completely; this is because the "sticking" does not happen unless the speed / RPM of the vehicle go over certain threshold so CVT does it's CVT thing. In other words - it will not stumble if I was sitting in bumper to bumper traffic, then inched ahead for 3 feet and stopped.

Link to comment
Share on other sites

There was an issue a couple other members had mentioned with CVTs stalling when coming to a stop after driving at speed. It sounds like you are having the same problem but your engine isn't completely stalling, it's almost stalling.


Other members that had the actual stall issue either got the CVT replaced under warranty or an update to the software. I can't recall.


Contact your dealership and let them know about the issue. Try to impress upon them you are worried about engine damage and knock because of the low rpms, rough idle, and near stall condition that happens repeatedly.

Link to comment
Share on other sites

OP, see if you can find a reproducible situation in which it always stall. I seem to recall someone on here saying theirs would stall consistently during a hard stop from 40 MPH when in manual mode or something specific like that, lol. Obviously you're gonna need to find a deserted airfield to figure out what works for yours...or just take it in for a CVT checkup.
Link to comment
Share on other sites

Well, took the Subie today to a local dealer; a different dealer than I usually go to. Had both TSBs printed out, letter from Subaru in hand, the above data ready - all in case that I need to be convincing someone there...


So I explained what is going on to the service advisor and he was just "Oh, a CVT issue; let me look it up in the computer... yup, you qualify. Your car has 83K miles on it so we do not need a pre-authorization. Cool!"


He then proceeded to say that they had a few like this already. Apparently, they first need to replace the valve body and then if that does not solve the issue, the Torque Converter. Left the car there.


We'll see how it goes but it seems like they will work on it.

Link to comment
Share on other sites

Well, interesting...


The dealer kept insisting that there is no problem. I kept telling them to try again. So this morning, went there and drove around with the service guy. The car stumbled once or twice but just a very small amount. Then, as we were in the car - the windows started fogging up so I turned on the AC. At which point, the car started stumbling more noticeably.


Then the service guy said that torque converter issues would be a lot more consistent than what I have and that he thinks there is an update for RPMs dropping down too much when AC is turned on. Went to his computer and sure enough he found the update. Applied it ($100) and now we will see.


I never did make a connection between AC on/off and this problem; most of the time we have the AC turned on, either for defrost or to cool, so I did not think much of it.

Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Create New...

Important Information

Terms of Use