Hyundai Forums banner

1 - 8 of 8 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
I've got a 2018 Sonata Hybrid, and I've noticed that my gas mileage is reduced by about 10% with Cruise Control turned on.

For example... the same 150 mile route gets 36 MPG with Cruise Control on... and 41 MPG with it turned off.

I've tried making changes to the adaptive cruise control (I hate that feature) and the Eco, Normal, and Sport modes.... but nothing seems to affect the poorer gas mileage.

This is evident by the position of the "power meter" needle and by "doing the math" on tanks of gas.

Has anyone else seen this? Do I need an ECU update?
 

·
Registered
Joined
·
475 Posts
This is my similar experience. The cruise control doesn't anticipate for MPG nearly as well as you can yourself.
 

·
Registered
Joined
·
559 Posts
My experience on my '16 is the opposite of yours. I'll be driving at 20% power (Normal mode) and turn the adaptive cruise on and the power drops to 10% but keeps the same speed. Using the cruise never causes a drop in mileage. I'm usually around 44 MPG this time of year. I only see the 30's in winter when the engine is running a lot for heat. Spring and Fall can get me into the upper 40's and low 50's.
 

·
Registered
Joined
·
1,735 Posts
2016 Ultimate. I usually get 44 to 47 MPG depending on the long drives. I have the smart cruise, always use it. Basically I point the car. Always in Eco
mode. Is your cruise always going 3/4 throttle to accelerate ? I am able to set mine not to go above 40% power, so it slowly fills any gap if a car moves out of the way. Middle setting goes to 80% and I bet high goes full throttle.
 

·
Registered
Joined
·
1,068 Posts
Are you driving on hilly roads?
If you let the car slow a bit going up hills and speed up going down you can get better mileage vs the CC keeping a steady speed.
 

·
Registered
Joined
·
2 Posts
Discussion Starter #6
Are you driving on hilly roads?
If you let the car slow a bit going up hills and speed up going down you can get better mileage vs the CC keeping a steady speed.
No, it's mostly flat... going 65 or 75 on a Interstate

Whenever I put cruise control on... I immediately see a jump in the "power meter" from about the 10 o-clock position to the 12 o-clock position. Take it off... and there is another immediate jump back to the 10 o-clock position.
 

·
Registered
Joined
·
475 Posts
I hate even setting mine, because it will overshoot and rev up a do odd things like that compared to any other cruise system I've owned. Mine is the SE and doesn't have any sensitivity adjustment but other higher end models do and that might help. I suspect it has to do with the ECO mode and such. I haven't experimented with how it works in NORMAL or SPORT modes. I suspect it might behave more normal in those scenarios.
 

·
Registered
2020 Sonata Limited (White)
Joined
·
59 Posts
Couple of comments; If you want to try NOT using the smart cruise function, with the cruise on, but not set, press and hold the following distance button. After a couple of seconds the cruise will shift from smart (SCC) to normal cruise (CC). You can also use this in the event that something is blocking the front sensor and smart cruise is disabled. You're cruise control will work just like any standard "dumb" cruise control.


About the power display - It appears to me that when shifting modes, not only does it affect throttle response, it also changes the Power display. It seems that for the same amount of acceleration, the power level displayed in Normal mode is less than Eco mode. For example, accelerating at 20% in Normal, is the same as 30-40% in Eco.


I have seen the same jump in power level when turning on cruise control. Since I'm usually in Normal mode when getting on the highway, my theory is that when you are using cruise, the power meter reverts to the Eco display no matter what drive mode is active, and causes the apparent jump in power level.
 
1 - 8 of 8 Posts
Top