2020 Cruise control issue

We are experiencing issues with the cruise control system on our 2020 TRD. While towing 3500lb boat I get a odd downshift then immediately back to previous gear. Example, cruise set at 55mph, small grade change rolling hills. As the vehicle starts to lose speed it will accelerate as expected then it will downshift for maybe 1 second then right back to previous drive gear. I’ve tried different combinations of sport mode...etc, nothing seems to stop it from happening. I can not duplicate it manually with the cruise off but I can tell you when it will happen with the cruise engaged. We previously had a 2016 and pulled same boat and never had an issue. We expressed this to the dealer, not a solid solution was given except it was “gear hunting”... not sure I buy it. I have also logged the issue/complaint with Toyota Corp. Yes maybe minor issue today but what does the future bring, trans failure??? I’m convinced somebody at Toyota Corp. knows the fix. I’m looking for a suggestions, any thoughts.

 

Welcome do the joys of an overweight underpowered SUV with a 5 speed.

 

I'm not sure what the question is here.

Towing --->Losing Speed ----> 4R downshifting to get back up to speed

Computer changes in 2020 possibly? You try changing cruise speeds?

 

Issue would be incorrectly downshifts, bounces down a gear then immediately back up. It is not needed to maintain speed, driving same route manually it won’t down shift. It seems to do it for sure in the 50-60 mph range while cruise is engaged, haven’t had it out at the expressway to try higher speeds. I am thinking computer mapping as well, again our 2016 never did this.

 

I know this feeling all too well, our other vehicle is 200hp JK Wrangler on 37’s. If you are wondering the 4R is like a Cadillac or should I say Lexus in comparison!

 

I have a 2020 and I believe what its the ACC. ( adaptive cruise control ) Something similar happened to me. I just turn it off for a sec and then when the road is normal or traffic is less dense I will reactivate it. No big deal. I love the ACC.

 

This. I know what the OP is describing. I've experienced it myself, usually on a steep hill. The answer is to just turn off cruise for a bit.

Or I guess you could continue to worry about it, but why? The 4L is a good engine, but these trucks are pigs with amateur cruise control programming. Easier to just drive around the problem.

 

Agree with the above, it’s the adaptive cruise causing the issue. Switch it to normal cruise control and the issue should go away.

 

Coming from new Fords for the last 25 or so years I think Toyota cruise control sucks.....along with their climate control and several other things.
Not sure how long this 2020 4Runner will be in my garage. Oh yeah....Ford Bronco on the horizon.

 

I have 2021 TRD and experience the same issue. I have figured it out. As I approach a hill, even the slightest incline, the sensor (even at the lowest sensitivity) sees the incline as an obstacle/vehicle for just an instance. I also notice it, but rarely, approaching some dark pavement changes, large patches, change from concrete to asphalt, etc. and even while passing cars that are in the right lane and not even in front of me. It's annoying. However, all works great as long as a vehicle is in front of me. No incline issues. Only see the problem when by myself and no vehicles in my lane. Toyota is definitely way behind literally everyone on electronics technology. Even my 2011 Dodge had a far superior audio for bluetooth, USB, and GUI for it all. I expected much better for 2021 Toyota.

 

It’s already been said but either use normal cruise or no cruise. Mine and my wife’s both do it. But we have figured it out somewhat. Wide open highway no issues. A vehicle in any lane within a few hundred feet it starts almost like it is pulsating the throttle. I didn’t feel comfortable with what it was doing so I don’t use acc anymore and just regular cruise. If you need help in regular cruise it is just hold the cruise button down a little longer and you’ll see a different icon pop up.

 

DO NOT tow with cruise control activated 'unless' you truly understand the dynamics of towing. DO NOT tow in 5th gear, 'unless' you truly understand the dynamics of towing. or is that just me?

 

Not just you, you said what I was thinking as I read through this