Actually, it isn’t a “fix” at all for the most part as it simply improves wear management in currently OK units. But it also provides a real fix (repair or replacement) for units that didn’t aged that well. From statistics and what we see in forums, those cases seem scarce.
The K313 itself appears sturdy enough with millions of units worldwide in the last 12 years without particular surge in complaints/fail rate. But firmware varies according to areas: NA fake shifts and/or paddles management might be in cause, who knows!
Anyway, updates are not uncommon in trans and other electronic components in modern cars. Not to be confused with, say, this specific batch of Honda with faulty execution leading those CVT to physically and abruptly break into pieces. Those were indeed a recall, not a service campaign.
Thank you for the clarification, Jolly! What I would like to know is what percentage effected CVTs have displayed the issue of a potentially dangerous speed limitation? Would anybody happen to know the answer to this? I am getting my corolla serviced next week, however once my warranty expires, I hope they would honor another “software update” should it be needed.
I would also love statistics. Right now the only public ones are from Consumer reports and TrueDelta (both on volunteer base) but not from Toyota.
Service campaigns are not related or conditional to warranties, but the good will (to maintain good marketing...) from manufacturer. Anyway, you should definitely get the current one if not already done.
By the way, the speed limitation ("limp mode") is not specific to CVT condition nor is it ever the problem itself. It's a "protection" mode modern cars enters whenever a problem of certain types is detected, whether with the transmission or something else, to prevent further damage. You'd still have to find what triggered it, it's not the issue itself (another area where toyotatalk is a bit off).
To be precise, not electrical but electronic (firmware). And “preventing” rather than “fixing”.
Under some conditions (apparently related to higher rpms), the original firmware might allow extra stress on the CVT. If those conditions are frequently encountered then one eventually might – not necessarily will – experience the real mechanical issue needing a real fix, which is premature wear of some CVT’s components. At this stage, it’s too late for the update, but repair/replacement is also covered under the service campaign.
Symptoms of this (but that can also have other origins) would be some erratic or mismatched rpms vs speed or throttle. It may or may not be subtle and gradual so the car’s computer might notice it before the driver. It would then trigger speed limitation (“limp”) mode, as it would for an array of problems. Since, again, speed limitation is a sign of a problem, not the problem itself, you’re then left with a bunch of suspects to investigate, including but not exclusively that “firmware vs certain conditions” induced CVT wear issue.
Excellent explanation. Assuming the preventative software update is performed, eventually my warranty expires, I begin to have issues with my CVT, do you think Toyota would fix the transmission if it needed replacing?
Theoretically yes but in actuality, probably not... You'd have to prove that the problem has no other cause than the original firmware AND that Toyota peformed the update without assessing the correct condition of the CVT at that moment (which they do, but Toyota, not you, has this data...)
That’s how it is for most, as most CVTs aren’t actually affected by the “premature wear” potentially induced, in some circumstances, by the original firmware. Some do notice a slight improvement, whether it’s only perception or the new firmware being more adapted to the current state of their transmission.