Adaptive Cruise Control Questions

Like the title says.... I've been pondering some stuff when it comes to Adaptive Cruise Control.

I have a 2020 SR 4x4 4 cylinder and since I purchased this truck I have been using the adaptive cruise control regularly, however a couple weeks ago I really started to actually wonder if using it is any good.

My questions are.
1. How does the truck slow down, obviously the algorithm predicts what's ahead and eases up on the throttle based on distance, but is there some sort of engine brake? Or does it utilize the actual braking system?

2. Could the consistent use of adaptive cruise control actually be bad for the motor/transmission?

3. When the truck has to abruptly slow down are the brake lights engaged?(I've wondered this on the highway cruzin 70 and then there are brake lights and we slow to 50 --- I'm assuming my brake lights are engaged)

I'm assuming the algorithm utilizes the braking system and engages the brake lights and that the continual use of the adaptive cruise control system is perfectly fine, but sometimes I wonder if it has any adverse effects on the engine/tranny.

 

I hardly use the adaptive cruise, I do not like how it brakes hard at times. My Chrysler has a much better system, it will let off the gas and coast a bit before throwing you into the dashboard…..basically seamless in operation with better anticipation of what’s ahead. The car will actually stop and take off again (which I don’t trust lol) but if you need to be stopping I don’t think you should be using cruise.
I’m sure it’s lighting the brake lights and as far as hurting anything on the truck I highly doubt it.

 

I hate the adaptive cruise control. If you hold the button in for like3 seconds if turns off that feature and then acts like the regular cruise control that you may be familiar with.

 

It mostly uses the brakes to slow down. I think it will downshift on long downhills, same as if you were riding the brakes, but I haven't driven this truck enough to know for sure.

It does turn on the brake lights, but maybe not quite as readily as if you were using the brake pedal.

I don't see how it could be bad for the engine/transmission. It could be bad for the brakes if you let it ride the brakes down a mountain.

 

No one in my family uses cruise control on their vehicles; (my wife, daughters & both son-in-laws)

I use it on Highway 1 here in Delaware but there are no steep hills...just slight up/down low grades of travel.

There are 3 bars of distance to select...depending on how much distance you wanna keep from vehicle in front of you.

As with any system, being familiar with the quirks of DRCC (Dynamic Radar Cruise Control) requires usage.

My assessment would be that all the safety requirements that make the automatic adjustments during DRCC do not hurt the truck.

My habits on the highway include keeping 3-4 car lengths distance from the vehicle in front of me...so when DRCC set to 3 bars, the display area lets me know it has sensed a vehicle without taking any action.

I'll either tap the brakes to turn off DRCC and manually view my situation or slide over to the fast lane to maintain speed.

It really takes a lot of swiveling on my head to be aware of my surroundings...as it should be for every driver.

If I don't like the flow of traffic, I'll tap the brake and turn off DRCC until the road becomes less congested.

I replaced my OEM grill with the vintage Toyota grill so I'm constantly testing the radar since it was moved slightly lower from original location.

I also engage LDA (Lane Departure Alert) testing the system for full functionality.

I've always wondered if the brake lights come on when in DRCC mode...I'm hoping it does.

 

I use it regularly and glad it’s available. I’m mindful of certain road conditions that might stress the tranny and engine such as steep hwy inclines. It’s like a dog, it will try to do what you ask even if there’s not a snowball's chance in hell the truck can do it.

 

I love the idea of it and use it sometimes. The part where I don’t like it for our trucks is that it tends to hold it in 5th gear instead of going into 6th where as when you are pushing the pedal it will go to 6th. The % of incline can be very minimal to none and it still does this. I had also wondered about the brake lights activating and feel like them must go on for safety regulations. Overall, it doesn’t work very well on our trucks unfortunately.

 

Thanks for all the responses. I have been using it on a daily basis for the past 4 years, so I'm very familiar with how it works and where I like to set it. I like the adaptive feature vs. the normal cruise control. I probably use this feature about an average of 200-300 miles a week.

I do notice in mountainous and hilly areas it is basically unusable.

Since I use this so frequently, My main concerns were if there was some type of engine braking that was happening internally that might potentially reduce the lifecycle of the engine/ transmission due to extended use of the feature and I was curious (although I figured it did) if the brake light came on when there was a braking / slowing down activity due to the radar algorithm.

 

As others said sometimes it is annoying when it hits the brakes in traffic. I find you can hit the gas to override the radar auto brakes and the feature stays enabled and doesn't disable like when you hit the brakes. Great for moderate traffic but combined with hitting the gas sometimes, works well in heavier traffic changing lanes etc.

 

Yes our trucks have a light version of engine braking, no it's not reducing lifespan. There is nothing mechanical about it to cause additional wear, it's caused by vacuum. It's actually better overall for your drivetrain because it causes less stress on components and extends brake life.

Adaptive cruise ultimately works the same as standard, it just has a radar to determine if there is something in front of you, and if there is match its speed if it's slower. It's literally controlling speed the same way you do when your foot is on the pedal, which literally just tells the car to add fuel or take away fuel. Need to go faster? Apply more gas. Need to stay at this speed, feather the gas needed to stay at this speed. Need to slow down, let off the gas and let friction slow the vehicle. Need to slow down faster? Apply brakes. When the physical brake are applied your brake lights are illuminated. They must by law.

Adaptive cruise also uses it's own shift schedule, so if you're tuned you are not using the updated and improved shift schedules. this contributes to it's piss poor performance on hills. It also doesn't want vehicle speed to drop at all, so it's very aggressive when applying more fuel to maintain speeds going up a hill, which is why it downshifts so quickly. It has very little tolerance.

Cruise control in general is less fuel efficient, because it pretty much prevents coasting. Without cruise when we try to keep a constant speed we fluctuate more, meaning we are off the throttle and coasting more often. Cruise does not do this, it calculates precisely how much fuel to apply to maintain that given speed, so it's almost never not applying fuel thus never coasting.

 

I would imagine it would not hurt the engine for braking.

I have OTT tune but have not used ECT while in Cruise.

 

Thank you very much for this detailed answer. Just what I was looking for.

I didn't figure it was bad for engine/transmission lifespan, however for the past 4 years I've been blindly just using this feature for hundreds of miles a week so I can tolerate my commute to work a bit better..... I recently started to ask myself these questions... It's nice to get an answer like this.
I personally enjoy this feature, especially in a base model SR truck .. I'm glad Toyota includes it as a standard

Thanks again

 

Every car built uses engine braking when slowing down. It’s simply a matter of fact with how internal combustion engines are built. Even when you’re in the brakes the engine is contributing to slowing the vehicle.

 

I have read close to the entire OTT thread but never contemplated before if a tuned shift schedule is used during radar cruise. Is it generally accepted by specifically the OTT folks that the tuned shift schedule is not used during radar cruise even with the standard OTT tune in place? That's the kind of unsung tidbit that makes it worth tracking some of these threads if true. Thanks.

 

I wondered about the Brake light coming on too. I put a brake light in the dash just for confirmation. When the engine brakes the light does not turn on, when the Brakes are applied by the cruise control the rear Brake lights are activated.

 

Can someone share what button they are using to turn of the radar on CC? All I can get it to do is to change the distance I allow between cars (3,2,1), but cannot turn off. TIA

 

When you first turn on cruise, hold the button in for 3 seconds and you'll have regular cruise without the adaptive feature.

 

It’s the cruise control button itself. Instead of pressing it and releasing to turn on radar cruise, hold it down as mentioned in post #3 and #17. This gives you regular cruise and the truck will maintain the set speed until you intervene. When you are in plain old cruise, the symbol that pops up on the dash is different than DRCC.
From the manual:
“With the cruise control off, press and hold the “ON-OFF” button for 1.5 seconds or more.
Immediately after the “ON-OFF” button is pressed, the radar cruise control indicator will come on. Afterwards, it switches to the cruise control indicator.
Switching to constant speed control mode is only possible when operating the lever with the cruise control off.”

 

Thanks!

 

Thanks> I wasn't picking up that they were referring to the stick.