Unusual ADAS issue above 100 km/h in my Hyundai Verna made me anxious

My service advisor told me that ADAS wouldn't work at speeds over 110 km/h and would get disabled automatically.

BHPian amg5610 recently shared this with other enthusiasts.

Greetings, fellow BHPians. Following my initial ownership review on my Verna turbo, this thread is about an unusual issue I faced with the ADAS system on the car a few weeks after delivery.

The Problem

A couple of weeks after taking delivery of the car in April '23, I started daily driving the car. My route involves taking the highway for a large part of my commute, bringing the issue to light. A warning popped on the instrument cluster when the car went over 100 kmph for over 5 minutes: "Vital forward safety functions are limited! Radar blocked." This prevented me from using Adaptive Cruise Control, and the Automatic Emergency Braking was disabled. The Lane Follow Assist still worked, as it depends on the camera rather than the radar. The warning message automatically gets cleared once the speed is reduced to below 90kmph.

This warning message made me anxious as it would make anyone who got a brand new car and is facing issues almost immediately. I first encountered this on a rainy morning and the road was dirty, so I hoped it would be a one-off and wouldn't appear again, but it wasn't! The same warning started popping up every time I went over 100kmph for over 5 mins.

Another thing I noticed was when I engaged ACC (I usually set it at 85kmph at Distance 2), the system worked in a rather weird way. It didn't recognize the vehicles switching to your lane, and the radar didn't recognise smaller vehicles such as bikes or auto-rickshaws. I couldn't get an opinion on this as none of my close friends or family has a car equipped with ADAS, and I don't have any past experiences with an ADAS-equipped car either. However, the reviews and videos I watched on YouTube all had perfectly working ADAS systems that recognized smaller vehicles and the vehicles merging in front of the car.

So I knew something was wrong with my particular vehicle but I had no idea what it was. I contacted my dealership and escalated this issue with their service department. They assured me that they would look into the issue and solve it when the car came in for its first service, as it was due in 1 week. When I took the car for its first service (1500km) 3 weeks after delivery, the technicians plugged in the OBD II device and looked for error codes, but there was only one related to the battery. It was cleared, and they took the car for a test run, assured me it was solved, and asked me to contact them in case it reappeared. Guess what?

The next day, it appeared in an identical situation (100kmph - 5mins). I again contacted my service advisor and was told he would take this issue up with Hyundai themselves as the ADAS tech was fairly new to them, and they haven't faced such an issue before, which is fair enough. A week or so later, I got a reply from my SA saying ADAS wouldn't work for speeds over 110kmph, so it gets disabled automatically, concluding that mine isn't a fault but it is a feature, and it is supposed to work that way. Classic response, as expected from the dealership. Their response didn't convince me and they were least bothered to investigate this issue further. I started looking for answers and researched online and looked at the owner's manual for any information; that is when I learned that the ADAS function should work for speeds up to 200 kmph. Now, I was pretty sure that it was a fault and not a feature.

The Culprit

Bumper. Yes, the Front Bumper. A few days later, I was watching some random YouTube shorts when I stumbled upon a video on factory accessories available for the Verna. I got a zoomed-in view of the front bumper and that car had a square plastic enclosing the Radar behind it, and I realised my car didn't have it. I checked mine immediately, and yes, it was missing in my car, which was the culprit. (Image attached below). I have no clue how it was missed during production and PDI. I was finally relieved that at least I had found the cause of the problem and it could be fixed.

The Fix

I contacted the dealership immediately as it was a manufacturing defect rather than a service fault. The technical advisor of the dealership remained in contact with me since the week the issue was discovered after delivery. I was told they contacted the PDI department of HMIL, and their people are coming to check my vehicle and fix it. As promised, my vehicle was taken to the yard, where the radar unit and the front bumper were replaced at no cost and returned on the same day.

A small protective covering for the radar caused all this and once the bumper was replaced, the issue was fixed. I didn't get any such warning messages at high speeds, and smaller vehicles and merging vehicles were also being detected by the radar flawlessly. I use ACC quite frequently on highways and I must say it is a big boon.

Here's what BHPian McLaren Rulez had to say about the matter:

If you get calls about feedback, please mention this. It is unacceptable to mislead the consumer this way. It happens so often that we're desensitized to it but it's still unacceptable.

These same SAs will then ask for a 10-star rating on a stupid review form and act offended if you give them anything that isn't a 10.

Here's what BHPian audioholic had to say about the matter:

I suspect the original bumper of your car which had this cover for the radar was replaced by a bumper of a car which didn't have ADAS and no one in the service center knew this consequence until you reported the issue and then they replaced the bumper or lower grill with the proper variant. It's nearly impossible for this to happen in the factory on the assembly line.

Here's what BHPian kpkeerthi had to say about the matter:

What protective cover are you talking about? A pre and post images would've helped.

Here's what BHPian audioholic replied:

Automotive radars need an unobstructed view in front of it, with respect to radar reflective material. They are physically hidden behind a plastic or even a ceramic cover whose reflections are static and are ignored after calibration. The moment this changes, to a different position or the plate is replaced by something else, the radar will end up realising that there is some unknown obstruction. Since this is a risk to its detections and there is a chance of wrong detection, the radar throws the error mentioned by the OP and the ADAS functions are degraded to different states, either partial operation or non-operation. That is exactly what happened in this case, with the Verna having two different lower grills for ADAS and non-ADAS versions. Someone has swapped the lower grille to the wrong version.

The correct grill has a flat blank area for the radar to function correctly

In this car, the grille has a design pattern which continues on the area ahead of the radar, possibly with some dark chrome finish. That will cause the radar to detect some abnormal objects ahead of it.

That is the reason I mentioned there has been some fouling at the dealer end as this mistake could never happen at the factory since the radars will be calibrated at the end of the assembly line and the calibration would have failed even if the assembly line really fit the wrong part on the car. Guess there was some transit damage or so and the part was replaced with the wrong replacement.

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