[GuyBurnsFuel]

Hi, I am here to seek advice/Suggestion/Help.

I own a 2020 Altroz XT MT. I dont use cruise control often. on my recent road trip, i used it for the first time.

It was a scary experience, the RPM does seems to be fixed but the car feels like it accelerates for 2 seconds then coasts for another 2 seconds & so on. is it normal for cruise control to behave like this ?
Whenever i cruise on highways, i just keep a light foot & RPS remains stable maintaining a constant speed, its very smooth but with cruise control, it feels scary.

is everything alright ? Do i need to get something checked from Service center? This is my first car with cruise control & honestly i have not met many people who own the car with cruise control. can someone help me with this ?

[warrioraks]

Originally Posted by GuyBurnsFuel

It was a scary experience, the RPM does seems to be fixed but the car feels like it accelerates for 2 seconds then coasts for another 2 seconds & so on. is it normal for cruise control to behave like this ?

Doesn’t sound normal. The CC on my 2012 Honda City shows no such behaviour on flat roads. It’s a pretty smooth affair with no significant signs of acceleration or coasting.
However acceleration or braking is apparent when the road has a steep incline (let’s say going up a flyover or coming down).
You should get this checked.

[Jeroen]

Originally Posted by GuyBurnsFuel

Hi, I am here to seek advice/Suggestion/Help.

I own a 2020 Altroz XT MT. I dont use cruise control often. on my recent road trip, i used it for the first time.

It was a scary experience, the RPM does seems to be fixed but the car feels like it accelerates for 2 seconds then coasts for another 2 seconds & so on. is it normal for cruise control to behave like this ? ?

Definitely not normal. A suggestion: did you check the owner manual on how to operate the cruise control. Best check.

By and large all CCs more or less work the same.

There is a button that switches the CC on. Note, that means you can now start using the CC. Then there is a button to “set” the speed and engage the CC.

So with the CC switched on, driving at say 60 km/h you press set speed and the CC will maintain 60 km/h. When you drive or down a hill it might slow down a bit.

But on a normal reasonably flat road it should hold a steady speed with no discernible hunting up and down as yours appear to be doing.

With the CC set, stepping on the brake or the clutch, the CC disengages, it remains on, but doesn’t control the speed anymore. On most CC there is a button that will allow you to “resume”. So you drive a steady 60 km/h with the CC on and speed set. You need to brake a bit, you slow down to say 50 km/h and hit the resume button. The CC will speed up your car until you drive 60km/h again.

Usually there are also two buttons that allow you to increase or decrease the set speed. You will find very often that some of these functions are combined in several buttons and or stalk.

You need to drive at a certain minimum speed before the CC speed can be set. Your owner manual will tell you. It is usually 30-40km/h, at lower speed you can’t set the CC speed, nor the resume function would work.

So better get it checked. Check with somebody who has an identical car.

Good luck,let us know what you find.

Jeroen

[GuyBurnsFuel]

Originally Posted by Jeroen

Definitely not normal. A suggestion: did you check the owner manual on how to operate the cruise control. Best check.

Yes, I saw more than a few videos on how to operate the cruise control, that doesn't seems to be the problem. I will go to the service centre tomorrow and see if I can have another Altroz there that i can take an opinion on.

[narayans80]

I've used cruise extensively on Corolla 4-speed AT and S-Cross MT in the last 5 years. There are subtle changes in rpm and speed depending on what sort of road you drive and to an extent the car's gear ratios.

My experience with respect to speed and rpm is as follows:

1. If you set the speed to say 80 or 81, the speed would subtly vary between 79 and 83 depending on the gradient. These are in GPS speed indicated by Google Maps/Sygic.
2. The RPM again would subtly vary depending on the gradient. I haven't looked too closely at the rpm meter. I expect 300-500 rpm
3. In an AT (case in point of Corolla 4 speed AT) when you are on borderline gear ratio. This change in gradient will induce a downshift. This acceleration is violent.
4. In an MT, if you set cruise for 80. Had to slow down to 60, now press RES. This acceleration again would be violent. I usually reach closer/above the set speed and press RES.
5. If you have your leg on the accelerator (consciously or not) . Cruise will still be engaged. But there will be additional speed and corresponding rpm gain due to your accelerator inputs. Cruise will disengage only if you press the clutch or brake.

Could you post the exact account of what rpm you observed and at what speed, what gear. This would paint a better picture of the behavior.

[GuyBurnsFuel]

Hi, i got it checked from Service center. My car had an old ECU, they upgraded it to AL04. The cruise control is working fine now & i am currently on a road trip getting 22 KMPL On flat road with cruise control. Speed - 85KMPH, AC Temp 23, Blower speed 1

[PrasannaDhana]

Originally Posted by GuyBurnsFuel

Hi, i got it checked from Service center. My car had an old ECU, they upgraded it to AL04. The cruise control is working fine now & i am currently on a road trip getting 22 KMPL On flat road with cruise control. Speed - 85KMPH, AC Temp 23, Blower speed 1

Geesh! Typical Tata inefficiency.

But then, shouldn't the cruise control work properly even on older ECU set up?

[GuyBurnsFuel]

Originally Posted by PrasannaDhana

Geesh! Typical Tata inefficiency.

But then, shouldn't the cruise control work properly even on older ECU set up?

Yes, it should have worked fine. When I asked the same they didn't gave me any satisfactory answer.

[mazealot]

I've had the same experience since the day we got the car , it usually happens when the speed is below 80km/h and the AC is turned-off . The car would accelerate upto the set speed and then would coast untill the speed gets dropped by a couple of km/h and then would accelerate again and this goes on forever . That said , i haven't experienced the same in the summers though, since its impossible to drive without AC in indian summer and the CC works just like any other car's CC in these conditions .

Also a little off-topic , but do you feel like the car's behaviour changes drastically when the AC is turned on ? The engine gets so sluggish , the shifts become so jerky and the engine takes an eternity to respond . Do let me know if mine's an isolated case or is it same for other's too . I have the 1.2L NA petrol .

[Nikhil Beke]

Originally Posted by mazealot

Also a little off-topic , but do you feel like the car's behaviour changes drastically when the AC is turned on ? The engine gets so sluggish , the shifts become so jerky and the engine takes an eternity to respond . Do let me know if mine's an isolated case or is it same for other's too . I have the 1.2L NA petrol .

Can't agree more: I have the same on my iturbo. A bit of drop in performance is to be expected for any car, but this is more than usual. This ends up needing extra-revving, which leads to drop in fuel efficiency as well. I find the problem especially with autoAC on. Plan to get AC module checked next week while the car would be going for service.

[GuyBurnsFuel]

Originally Posted by mazealot

...Also a little off-topic , but do you feel like the car's behaviour changes drastically when the AC is turned on ? The engine gets so sluggish , the shifts become so jerky and the engine takes an eternity to respond . Do let me know if mine's an isolated case or is it same for other's too . I have the 1.2L NA petrol .

Yes, i drive the same NA engine & i can confirm that car's behaviour changes a lot. It's exactly what you described. Also on the side note I used to drive a 2006 wagon R LXI 1.1L 16 valve & i really miss her gearbox. If AC is turned on, you need to put Altroz in first gear if the speed drops below 10 kmph, with wagonR you can have it in 3rd gear & it would still pick up.

Altroz is best suited for open roads where you can put her into cruise & relax. The engine is super smooth & there is no noise inside the cabin.

[John P Daniel]

Originally Posted by GuyBurnsFuel

It was a scary experience, the RPM does seems to be fixed but the car feels like it accelerates for 2 seconds then coasts for another 2 seconds & so on. is it normal for cruise control to behave like this ?
Whenever i cruise on highways, i just keep a light foot & RPS remains stable maintaining a constant speed, its very smooth but with cruise control, it feels scary.

As far as I can tell, it's normal in mine as well. It accelerates to it's threshold speed and then coasts for few seconds till speed drops below the lower threshold and then it accelerates again. It's more noticeable when car is loaded. But it's like within tolerance of about 1-2kmph max. When lightly loaded, it's barely noticeable. Similarly, when AC is running, based on load, the speed varies slightly as well.

BTW, I've experienced the same effect in my acquaintance's Fiat Linea Diesel as well. It coasts for a few seconds after the set speed is reached.

Originally Posted by mazealot

Also a little off-topic , but do you feel like the car's behaviour changes drastically when the AC is turned on ? The engine gets so sluggish , the shifts become so jerky and the engine takes an eternity to respond . Do let me know if mine's an isolated case or is it same for other's too . I have the 1.2L NA petrol .

Same here as well. When the AC is turned on initially, the AC runs at full capacity and reduces engine performance quite noticeably. Once the AC settles down, the load is reduced as well.

Altroz has variable type of compressor and it runs continuously. It's adjusts it's load based on the cooling requirements and conditions. In my car, once the set temperature is reached the car's performance becomes nearly normal again.

[GuyBurnsFuel]

Either i am the most efficient driver or this MID is completely wrong. .
Getting 30KMPL from Altroz driving on a straight highway at 60 kmph with cruise control & AC off