Dacia Stepway AEB activating itself

techie

Hi, my wife has a 2024 Stepway 1.0L and recently in all driving conditions the AEB (Auto Emergency braking) is deploying itself without warning

The car is currently in the Main Dealer for the 2nd time for this issue, which almost caused my wife to have a crash on Friday with it,

Has anyone else with a newer Dacia had this happen and what was the resolution for it?

Main Dealer last time said no fault found and gave us a 3 page doc from Renault on what could cause it,

Not accepting that this time as car is dangerous now!

Henry Ford III

Sounds dodgy and potentially dangerous too. Thankfully it'll still be under warranty.

GPoint

Was she driving under the bridge or in the rain when the car decided to brake?

techie

https://www.boards.ie/discussion/comment/123815058#Comment_123815058

No, it has happened at random times, never under a bridge or raining yet, I assume you mean shadows and why rain?

techie

https://www.boards.ie/discussion/comment/123815058#Comment_123815058

Yes, but according to dealer its not logging any errors in cars computer, so hence why they now have it for 2 weeks to see it for themselves?

nu_90

This might sound mad but , I’ve heard this happen before to a friend in work , drives cupra Ev born , happened him on motorway going under a bridge. Was told by his dealer to keep his front bumper and windscreen camera cleaner. As in wash his car more often !! As it has a lot of tech in front.

Often think about it when washing my own car , to the point that I’m not gonna get next car with this amount of safety tech.

Sounds mad right?

techie

https://www.boards.ie/discussion/comment/123816784#Comment_123816784

I am aware of that, and have been keeping the sensor on front clean, its still happens and it happened my wife 4 times on Friday last , the last of which a guy behind her had to swerve to avoid her, rang Dealer and told them she is not driving car again , they drove a spare car to her, and they have it now, we have had the car new since last April 2024, and this only started happening recently, so something must be wrong with it?

GPoint

I had only 2 issues similar to what you describe over 2 years of driving but with a different car.

One was merging from M50 onto N4 where you go onto the ramp and it splits into two. Had the car braking for me but the car in front was very far.

Other instance was was when I approached a roundabout in heavy rain and started moving after a long lorry had just cleared the roundabout but left behind a trail of water so the car stopped just after I tried to move off.

From this I concluded that these system may misinterpret surroundings in some rare occasions.

kirving

Do the activations have anything whatsoever in common?

• Is she already braking when it occurs
• Is she following too closely?
• Still accelerating toward stopped traffic?
• Is is on a narrow road?
• On a tight bend?
• Oncoming traffic?

Has the car got any other problems like slipping clutch?

Do the brake lights work with the slightest press?

As far as I know, it's a Radar only based system (whereas some are Camera and/or Radar) - so it's not going to be shadows or rain causing it.

techie

https://www.boards.ie/discussion/comment/123819273#Comment_123819273

I will answer them in order:

1. No, driving along normally
2. Nope, most times nothing and I mean nothing in front of her
3. As above
4. One time yes, on a narrow road
5. Never on a bend
6. No traffic coming

No other issues, clutch is fine , car until start of August was flawless

Not sure about slightest press, but work as normal from what we know

There seems to be no cause for it, I have seen it twice myself while driving, both times on an open road, with no traffic, bringing my daughter to school early morning,

These are very specific questions, do tell? :)

kirving

https://www.boards.ie/discussion/comment/123820068#Comment_123820068

Actually, does the car have lane assist too? Most I've seen online don't seem to. Is there a front camera?

Generally, AEB systems are quite conservative - they will sooner brake as late as possible, and prefer even to just reduce the severity of an actual crash, than brake for no reason.

Usually - they have to be 99% sure you will actually crash before they activate - but other things will come into play too.

If you ride the clutch, come off the accelerator too quickly, or tap the brake at the same time as a radar detection - the car can think that you are also reacting to a possible collision, and escalate what was maybe a low confidence detection of an object - to a full AEB intervention. A faulty brake or clutch switch can feed bad data into the system.

The radar will monitor the distance to the car in front, and look at how quickly that distance is increasing or reducing. If you're already braking, it will assume that you're going to brake harder, and not necessarily react. If the pedal switch was faulty - it might react more aggressively. If you continue to accelerate towards a stopped car - but plan to brake, the car might assume that you haven't see the car in front and again react early.

Assuming none of that this occurring though, as you say there is nothing in front of the car - does it happen in the same place on some roads? Could you share some Google Maps locations of where it has happened?

techie

No, our car does not have lane assist, only front radar for AEB.

Our car is totally random, except it does not do it on motorway or with cruise control on (So far!)

It according to my wife, does it between 50-80kph on A roads.
Its totally random but now getting dangerous with wet weather coming in, there is never a car in front too,

The garage rang today to update that they have not seen the issue YET!

Anyone here know what my options are if they don't see the issue for themselves and try to give us back the car?

_Kaiser_

Has it happened with you driving the car? Is it possible she's doing something in particular to trigger this?

techie

https://www.boards.ie/discussion/comment/123824384#Comment_123824384

Yes it has happened to me also, driving along a straight road, early morning, with my daughter in car, nothing in front of us, and car starting beeping, Brake up on screen and I had to press the accelerator hard to counteract it

prawnsambo

https://www.boards.ie/discussion/comment/123824801#Comment_123824801

Might be worth getting a dashcam and mounting it so it can view the dash as well as the front windscreen view. It would then give you video evidence for the dealer if they fail to find anything on test.

kirving

https://www.boards.ie/discussion/comment/123822446#Comment_123822446

Yeah I was thinking it could have been the Lane Departure, which commonly brakes one wheel rather than actually pull the steering with a motor. Looking online though - people have reported phantom braking as an issue with Dacia.

I'm just asking the below to try and get a better idea of the root cause - not to excuse it happening, or to take responsibility off Dacia.

1. Do you have any aftermarket add-ons to the car like a hardwired dashcam?
2. Have you ever noticed the car battery to be low?
3. Does the car track perfectly straight, with the steering wheel returning to dead centre when you let go?
4. Was any work done on the car where the center console was touched? (this is likely where the car's accelerometer and gyro sits).

The reason I ask 3 & 4 is that if the car sees an object off to the side, but thinks you're turning toward it, it could activate the AEB.

I'd be astonished if the AEB activations weren't stored in an ECU on the car which could be checked by Dacia. The below is not definitive by any means, but shows that even regulators are interested in logging being required.

techie

@kirving Thanks for taking the time to answer here, its much appreciated!

1. Car is totally stock, no mods whatsoever
2. Never noticed the car battery to be low, always starts on the button
3. Tracking is perfect, yes steering returns to centre and no vibrations
4. No work done other than regular services with dealer its with at the moment

According to the Dealer, I can name them, if that's allowed? Its not registering any AEB events??

I am fully convinced they will try and give me the car back after driving it for 2 weeks and say No Fault found,

If that's the case, then I am going to demand a report from them on their letterheaded paper stating car is perfect and they recommend its fit for purpose to drive safely on the road,

I don't want this to cause a crash with my wife and kids in the car, due to their lack of interest/competence etc.

Sorry for Rant !!

techie

Update call from Garage earlier, it happened to their Tech while driving so they now have seen it for themselves, so relieved.

They said they can't release it back to us like that as its not logging the AEB events, so they can't find what's causing it.

What do you think they will do next?

ongarite

Replace the windscreen camera, quick search of Dacia forums points to this as likely cause of issue.

techie

https://www.boards.ie/discussion/comment/123831316#Comment_123831316

There is no windscreen camera on our car, just the radar sensor below the bumper at the front?

kirving

https://www.boards.ie/discussion/comment/123831306#Comment_123831306

That's great news to be honest. Hopefully they'll now have incentive (and justification) to look at the logs in much more detail and get an answer.

techie

https://www.boards.ie/discussion/comment/123831869#Comment_123831869

Yes, they did say Logs are not showing any events though, so not sure what they will do with that, I asked about replacing the radar as a precaution and they said they can't under warranty until it shows them an error, so not sure where we go from here now?

_Kaiser_

At least they've been able to replicate the issue and they are taking it seriously if they're unwilling to give it back to you as is.

You'll need to ask them what the next steps are and a timeline. This could go on for weeks if they can't get anything from the logs. Even if they start throwing parts at it, it'll be trial and error by the sounds of it.

Who are you speaking with in the dealer? If the service manager then you'll need to go higher than that I'd say. It depends on what you want though at this point - are you willing to let them troubleshoot it further? Replacement? Refund?

Might need a call to Dacia Ireland if you don't get anywhere though.

techie

https://www.boards.ie/discussion/comment/123835108#Comment_123835108

We are dealing with the Service Advisor, the Service Manager is on holidays until Monday, so will be ringing him then, Dacia Ireland are involved in the background but they have advised me that the dealer is dealing with it?

What are our options though as car was bought new by us in April 24, can we ask for a replacement car as we do need it?

_Kaiser_

I would expect that as a minimum they should be providing you with a temporary replacement as your own is under warranty and they are unwilling to give it back in its current condition.

The fact that Dacia Ireland are already bouncing it back to the dealer wouldn't be a great sign to me - but that's me. I am just imagining both sides passing the problem between them if they can't figure it out.

Fundamentally it's a serious safety concern that makes the car dangerous and unusable. I would be giving them another week to get to the bottom of it and fix it (they've already had it at least 7 days from your OP plus the first time you brought it in), and then I'd be pushing for a replacement or refund myself. Make sure you insist on that temporary loaner in the meantime.

That would be my approach.

techie

https://www.boards.ie/discussion/comment/123835222#Comment_123835222

Thanks, they have given us an old Duster while they have our car, I will approach it as you suggest as my wife loves the car but she has lost faith in it now since she was almost in a crash because of it

_Kaiser_

https://www.boards.ie/discussion/comment/123835244#Comment_123835244

I'd be polite but firm. If they are already saying they can't take actions without logs and Dacia Ireland are pushing it back then it could go on for weeks like that.

If your wife is reluctant to have it back (and I can't say that I blame her) then I would be inclined to move straight into the replacement/refund discussion - how long have they had it in total at this point? (including the first attempt at fixing it).

The service manager won't be able to approve that of course, so you may need to take it to the dealer owner but be firm.

I once had an issue with a dealer (not Dacia to be fair) where they had done work without my approval and wanted to charge me several hundred euro for what was supposed to a warranty diagnostic and recall job. Service manager said he wouldn't give me the car back until they were paid.

Over the next hour I got onto the sales guy I'd bought it from who gave me the owner's number. He wasn't thrilled about being called at some event in the UK but by the time I got back to the garage, my car was ready and keys handed to me without any more about it. Never went back to them again.

Just be clear, calm and polite but make sure they are under no illusion as to what the end solution needs to be.

techie

https://www.boards.ie/discussion/comment/123835294#Comment_123835294

Thanks Kaiser, they have had it in total now 3 times for this issue, this time is the longest, 1 week already, and my insurance at the moment is set to next Friday at their request on the loan car.

The service manager is back on Monday, so will leave it with him until Tuesday morning, as he is aware of it,

I will ring him then Tuesday and as you say be fair but firm, that we need a resolution from them by end of week,

We would ideally prefer a different car, but not sure we are within our rights to suggest that?

_Kaiser_

Well if they've had it 3 times already and still can't fix it, then it's definitely time to start talking about replacements or refunds in my view.

The key is that the car is dangerous - as admitted to by themselves by not wanting to give it back now that they've been able to replicate the problem.

That's what you lean on. That trust in the car is lost especially as they can't identity the problem with it either (and they're the experts after all).

See what they have on their website - if you can find another of the same year, mileage, and spec in stock, push to have a look at that with a view to swapping - assuming that your wife is willing to have another of course!

The service manager won't be able to agree to that alone though but don't hesitate to ask to get the owner of the dealer involved if needed.

Be prepared to get legal advice if needed. If they refuse to play ball it might be your only option. Ignore any talk of SIMI. They are a dealer lobby group, not a watchdog (although a lot of people seem to think they are).

Also be prepared to push with Dacia Ireland again. Fundamentally the car is no longer fit for purpose, no one knows what's wrong with it, it's in warranty and you've been more than patient. Now you expect a proper solution.

10-10-20

Full marks to Kirving on this. Very interesting reading.

The point about logging is critical as the lack of logging is worrying as otherwise you are the crash-test-dummy for a poorly engineered system. If it ever came to it and i was in an accident where the safety systems failed, I'd prefer to die in the accident and know that my innocence was recorded rather than let a corporate entity dismiss the accident out of hand as being driver-error, and be free to absolve themselves for lack of evidence.

Adding logging and data retention to a system adds cost, thats why its not done by default.

But even then its not always guaranteed that the corporation will disclose the evidence...

https://arstechnica.com/cars/2025/08/how-a-hacker-helped-win-a-wrongful-death-lawsuit-against-tesla/

trellheim

That the OBD/ECU is not logging the activations is worrying in itself, even on my Lexus I can click in and see what the faults are.were if you have the diagnostics.