C4 Cross 2022 HSA (Hill assist) problem

[Citro]

Hello, I own a new C4 Cross 2022 with automatic transmission, electronic brake, petrol 130hp. When the car stops while I am pressing the brake, and the engine stops, and the road slope is small to moderate, then the HSA does not work 90% of times or more. As a result, when I am moving my foot and press the accelerator, the car slides backwards from 1 to 40cm, before the clutch does its thing and start moving the car forward. It has moved backwards more that 40 cm, but these occasions are rare. When the road slope is higher, the HSA seems to work fine, although I rarely drive to such slopes. The problem is that everyday, driving around where im living, this problem happens tenths of times, resulting in anxiety and risk of hitting anyone at the cars back.

The car shows no error, the official garage diagnostic control shows no error, data sent from officials garage to Citroen France were supposedly not indicating any problem. I am wondering if they collected the data using an appropriate protocol. Moreover, videos showing the symptom were sent to to the official garage and they also sent them to Citroen France. in all videos the car moves backwards more that 20 cm One video shows the car moving backwards and another video shows the car not moving backwards at the same point at the same road. This is enough for me to prove that HSA is not working correctly.

Anyway, I would like to ask anyone who could share his experience:
1. Does the car moving backwards up to 40 cm, happens to other Citroen cars with HSA?
2. Do you consider this symptom as a problem?
3. Should Citroen consider it as a problem?
4. If I hit someone's knee from this moving backwards HSA fault would it my or citroens fault?

Regarding question 2:
I only can only accept it as a problem when driving at the city. But even when someone doesn't not want to consider it a problem I am challenging him since:
-Start stop is by default "on" whenever I turn the key to Strat the engine. This means that when driving in small slopes in traffic, the engine would stop (most of the times) when the car stops. You do not bye a car and I am guessing Citroen's intention is not to sell a car that in order to be safe, the driver has to manual change the start stop settings even time he stars the car.
-When the car stops, the transmission does not hold the car from moving backwards. Only the brake does. Im not talking about electronic hand brake because one cannot drive in the traffic using it.
-Thats the main utility why the HSA exists: it brakes the car because the car stops with its engine turned off, which means that it will lag for 1-2 secs max for the transmission to hold and move that car forward, when the engine starts.
-Otherwise, engine Start Stop should not exist on an automatic transmission car with electronic brake. Since it exists and forces me to use it in "activated" mode every time I turn the engine key, this means that HSA should work.

Thanks for listening to me.

[GiveMeABreak]

You don't really have any come back regarding if you hit anybody or another vehicle as a result of the HSA not working. The reason being it is a feature and not to be relied on solely for stopping the vehicle. It will clearly state this in your handbook. As the driver, you are responsible for the vehicle and should always use the handbrake (electronic or manual) to immobilise the car in traffic.

Over-reliance on features like this makes the driver lazy and it's a habit nobody should get into.

Citroen may well check or replace the angle sensor on the vehicle, but generally speaking, do not rely on assistance systems to take the place of good driving.

It's another reason why I would never use a Tesla with autonomous driving as the system has caused no end of crashes. According to the US Department of Transportation, 474 out of the reported 605 crashes were Teslas with Autonomous Driving modes.

[Citro]

You don't really have any come back regarding if you hit anybody or another vehicle as a result of the HSA not working. The reason being it is a feature and not to be relied on solely for stopping the vehicle. It will clearly state this in your handbook. As the driver, you are responsible for the vehicle and should always use the handbrake (electronic or manual) to immobilise the car in traffic.

Over-reliance on features like this makes the driver lazy and it's a habit nobody should get into.

Citroen may well check or replace the angle sensor on the vehicle, but generally speaking, do not rely on assistance systems to take the place of good driving.

It's another reason why I would never use a Tesla with autonomous driving as the system has caused no end of crashes. According to the US Department of Transportation, 474 out of the reported 605 crashes were Teslas with Autonomous Driving modes.

I do not agree with anything you are saying. Im sorry. My point has nothing to do with "laziness" and relying on assistance systems. My point has to do with 1. HSA itself, if anyone driving a car with HSA considers its working properly, 2 Citroens responsibility in fixing it, 3 arguments that I feel that cannot stand for this HSA behaviour from the point of a corporation-customer promise within the EU legislation.

-Please, tell me if you have the experience to say if 20, 30 and 40 cm backwards movement seems reasonable to you.
-The hand book says that HSA cannot be disactivated, while I have told that sometimes it works for the same slopes that it mostly doesnt work. Does this say something for you?
-The feature, as you call it, cannot be deactivated by design, and as I have told, Citroen's by default setup of engine start stop is "enabled" for every time you turn the engine key. This makes the HSA feature necessary to work at everyday casual, numerous small and medium slopes. other ways it should not exist. If hill asset didn't exist and start stop could be set up to default as deactivate, then we wouldn't talk.

What you actually are saying to me is that I should not rely to HSA, This means that I have to deactivate the start stop every time I start the engine. How does it sound to you having to do this every time so as to overcome a feature I do not have to rely to as you say? This is clearly an overcome for a problem, and not a decision for not using a feature.

The second workaround is to use the electronic hand brake. This again is getting out of proportion here. Have you ever used electronic handbrake 10 times for a distance of 50 meters in traffic, for slopes 2-6%? Multiply it for a daily use and multiply it for a monthly use. It is not logical, practical, fast and its not meant to be used in this way. As it is not practical to turn the engine off so that electronic handbrake and P mode activates.

[DeuxChevaux]

I think the clue is in the name - Hill Start Assist. It seems you want it to work on nearly flat roads and as you say it works on hills. Not sure how quickly you are from firm pressure on the brake to the throttle as on a level(ish) road I would not expect the car to move very much at all even without HSA. If you are not happy with the car take it back to the dealer for assessment.

[Citro]

I think the clue is in the name - Hill Start Assist. It seems you want it to work on nearly flat roads and as you say it works on hills. Not sure how quickly you are from firm pressure on the brake to the throttle as on a level(ish) road I would not expect the car to move very much at all even without HSA. If you are not happy with the car take it back to the dealer for assessment.

Of course it takes much less than a second to move from brake to acceleration pedal.

Hi, thanks of the reply but I am as precise as possible: The gradients that lead to up to 40 cm backwards movements. And it has moved more than that but only 2-3 times.

So its a logical fallacy to say that I want it to work for nearly flat roads, since that at nearly flat roads the car should not move backwards at any level that any sane person would care. Except if you think that e.g. 30cm backwards movement is acceptable.

Im talking about the symptom giving numbers and I am not making assumptions. The talking here is results driven and not assumption driven. Thats why if you read carefully my post I give all the precision evidence that I believe show a malfunction. The next phase in order to talk here is to go and measure the road incline, and organise an experiment in a way no Citroen engineer would ever do.

But without making assumptions, do you know of any car that would go back as much as mine?

[GiveMeABreak]

Agreed, if you're not happy take it back. Stop start cannot be deactivated, but guaranteed it will stop working within about a year anyway, once the battery falls below a certain charge.

Mine works fine, and I use the hand brake on hills regardless of HSA, but I never rely on assistance systems for 100% of the time.

arguments that I feel that cannot stand for this HSA behaviour from the point of a corporation-customer promise within the EU legislation.

Please quote me the legislation you are referring to as I am not aware on any guarantee of any such HSA systems in EU law. Vehicles are required to have brakes and a handbrake.

As far as Citroen goes, as I said, they can test the angle sensor, but the system will only work with the engine running and gradients of over 3% with Stop Start vehicles.

[Citro]

Agreed, if you're not happy take it back. Stop start cannot be deactivated, but guaranteed it will stop working within about a year anyway, once the battery falls below a certain charge.

Mine works fine, and I use the hand brake on hills regardless of HSA, but I never rely on assistance systems for 100% of the time.

arguments that I feel that cannot stand for this HSA behaviour from the point of a corporation-customer promise within the EU legislation.

Please quote me the legislation you are referring to as I am not aware on any guarantee of any such HSA systems in EU law. Vehicles are required to have brakes and a handbrake.

As far as Citroen goes, as I said, they can test the angle sensor, but the system will only work with the engine running and gradients of over 3% with Stop Start vehicles.

Thanks, for the reply and the battery info. I never rely 100% to such systems thats why I double brake to make the clutch engage. Just as info I come from 106 rally, swift sport, Clio with some modifications, focus and fiesta, for a reason. Using the electronic hand brake for a casual 5 km route to work with slopes of more than 3 % and less than 10 % for every 5 seconds, is not something any car manufacturer would want and no driver would accept.

The problem is that an official Greek Citroen service center ( I do not know how to name it, its not Citroen Greece, yet) does not recognise any fault since Citroen France told them that everything is fine! So something is wrong here and someone do not want to go on further on this. Of course I cannot send it back to them, they will not accept it because for them there is no problem.

Their problem is that they cannot make use of the Citroen warranty and apparently they do not want to start changing electronics till its fixed, with them paying the cost.

So I have to prove that it doesn't work for gradients more than 3 percent, and take videos of that. I have the videos but I do not have measured "officially" the gradient. I am wondering who will officially verify the slope of the road that the videos show the backwards movement. its getting silly, I know.

Regarding legislation, the only I know is that there are laws that lawyers interpret them in the way courts accept. There are also directives and guidelines from the EC. And in general there are "ways of thinking" that protect for the justice itself. There is logic that a judge counts on. otherwise there would be a law for every fact. This is not the case, and law science is not about that. So, when any Citroen promotes start stop with stop as default, declares that HSA works for over 3% inclines, and I hit a pedestrian trying to pass through a small "window" between my car and the one on my back, then a court who is to blame? Should any Citroen should have a responsibility especially after I have tried and documented the symptoms of my car to any-Citroen itself?

[GiveMeABreak]

Unfortunately this is how it works with most dealers. In order for any warranty claim to be made, a guided diagnostic has to be undertaken using their specific diagnostic tools and server connection. This is essential for electronic components, as in order for the dealer and Citroen to make any warranty claim themselves, they must gave the clear evidence from the diagnostic tool. If nothing shows up, and they cannot see ore replicate a fault, then they can't make a claim.

The HSA is a feature controlled by the ESP ECU, which handles all the stability control features and controls the electronic handbrake too. My C3 Aircross (with manual handbrake) works as it should on hills or steep inclines, but goes not stop slight rollback on roads at traffic lights where the road is on a slight incline, which is fine and I don't expect it to. And just to confirm, when operating, it holds for at least 2 seconds when taking your foot off the brake on a hill.

If you have your VIN I will check to see if there are any technical bulletins published on this issue (please post your VIN in full without spaces - it will be automatically masked from public view after submitting your post & will only be visible to staff).

[Citro]

Unfortunately this is how it works with most dealers. In order for any warranty claim to be made, a guided diagnostic has to be undertaken using their specific diagnostic tools and server connection. This is essential for electronic components, as in order for the dealer and Citroen to make any warranty claim themselves, they must gave the clear evidence from the diagnostic tool. If nothing shows up, and they cannot see ore replicate a fault, then they can't make a claim.

The HSA is a feature controlled by the ESP ECU, which handles all the stability control features and controls the electronic handbrake too. My C3 Aircross (with manual handbrake) works as it should on hills or steep inclines, but goes not stop slight rollback on roads at traffic lights where the road is on a slight incline, which is fine and I don't expect it to. And just to confirm, when operating, it holds for at least 2 seconds when taking your foot off the brake on a hill.

If you have your VIN I will check to see if there are any technical bulletins published on this issue (please post your VIN in full without spaces - it will be automatically masked from public view after submitting your post & will only be visible to staff).

Thanks for the response. I will post here the VIN. Today I spoke with the head of service. He told me that the car can go up to 8% of the cars length backwards, and after that the transmission keeps the car from rolling. But he also told me that he does not have access to any gradient spec where hill assist starts working. I "know" it must be 3%, And the story of 8% of the cars length I suppose is not a proper answer because hill assist's work is to keep the brakes active and thus the car doesnt move back. The 8% story must be something different. So I will measure a test road incline (that my idea) and go with him with another C4 he will drive and test the two cars. If mine rolls back and the other does not, then I suppose he can make a claim.

Its something although I believe the absolute answer it if Citroen France could give him (official service of Citroen Greece) the gradient threshold for HSA and then I can make test and claim based on this.

If other cars have similar reported cases, then Citroen will try to find a solution, so right now my case could be just an outlier.

FYI, I asked him and he told me that the gradient sensor is integrated in ABS module and its price could be something like 2500 euros.

Again thanks for your support!

[RichardW]

I have on occasion thought our C4 (manual) wasn't holding when it should. I wonder if there is min brake pressure required to activate the hill hold. Try pressing the pedal harder before you release and see if that makes it hold.

[Citro]

I have on occasion thought our C4 (manual) wasn't holding when it should. I wonder if there is min brake pressure required to activate the hill hold. Try pressing the pedal harder before you release and see if that makes it hold.

I have heard about it but I think it was for another and older model. I have actually tried it and I did see any difference. The problem is that for smaller inclines HSA works and for bigger inclines it often does work unless the inline is much bigger.

[Incisive1]

I currently have this car as a hire car for the week and I have always been paranoid about damaging hire cars. The hill starts Assist issue is giving me anxiety so I have figured out that once you disable start stop that it is absolutely fine. there is a button on the dashboard below the screen on the right with a car icon, press that and disable start stop and hill assist L works like a dream. What a nightmare

[GiveMeABreak]

Hill start assist works fine in all conditions and has nothing to do with the Stop Start, just how you use it. There are other factors that are taken into consideration as to how HSA is operated, including the state of the pedals, the incline etc and is handled by the ESP system.