2021 Hyundai Elantra Collision Avoidance Problems

Your forward collision warning system randomly activates and disables itself, which has happened at least 3 times since you bought the car in July 2025. The system triggers error code C1620078, and records show the previous owner experienced the same issue. The dealer told you everything was normal without inspecting the vehicle. Fixing this will likely require a diagnostic scan and possible replacement of the collision sensor or its wiring.

Your forward collision avoidance sensors have been failing intermittently since 2021, especially during rain or snow, but also recently on clear days with no visible obstruction. When the sensors fail, the system turns off on its own, and the latest failure won't reset, which creates a safety concern while driving. The issue may require sensor replacement or recalibration by a technician.

Your forward collision avoidance system is triggering warning lights on your dashboard, including the Sensor Check Forward Safety System message, along with ABS and Auto Hold lights appearing unexpectedly. There's no visible damage to the sensor itself. This will likely require diagnostic scanning to identify what the sensor is detecting or if there's a wiring or electrical issue with the safety system.

Radar equipped to front of vehicle has malfunctioned, disabling all forward safety systems and adaptive cruise control. Without this equipment functioning, cruise control is completely disabled and the vehicle will not automatically brake or provide forward warnings. The vehicle component has not been inspected, but this is a recurring issue amongst other owners of this model. There is a warning lamp that turns out that states "Check Forward Safety System"

Several times, including yesterday, my forward collision avoidance engaged by braking suddenly and strongly and INAPPROPRIATELY, almost causing me to be rear-ended. I was nowhere near the car in front of me, and fortunately due to traffic was traveling below the speed limit. This seems to happen whenever there is an overpass above the road. I have reported this to Hyundai, and they don't seem very concerned. Very dangerous. I would think there could be a software or sensor update that can correct this situation.

Over the past 4 months, this car's safety sensors have randomly activated on 4 different occasions. The car will suddenly brake when this occurs, which puts me and the other drivers around me at risk of crashing. Each time, I've taken it to a Hyundai dealership for repairs. They always claim they can't recreate the issue and don't fix anything. I've provided the dealer with pictures and videos of the warning lights on my dashboard. It doesn't seem to help them diagnose the problem.

Forward collision sensor suddenly failed to function properly. This issue was NOT caused by any damage or a collision; it happened while driving on the highway. Hyundai does not fix this under any warranty, even though the issue was not caused by damage. It appears to be a bad quality/faulty sensor.

Pop up display "Check Forward Safety System and Check Smart Cruise Control System" during driving on the free way with no reason. 3 month ago same thing happened. fixed that problem with re-calibration to the front sensor. But. same problem happen today. This problem is recalled in south korea on last year.

vehicle only has 14k miles and is showing an error message for "check forward safety system" and "check smart cruise control system" after some research found this is a very common issue with multiple Elantra's where the front radar goes bad causing safety systems such as automatic braking/acceleration, and cruise control to not work. this is a big safety issue that has been reported by many drivers. the error happened going a steady 40mph with no other cars around on an open road. nothing was hit the radar just suddenly failed

While my son was driving on the highway, the smart cruise control suddenly stopped working with "Check forward safety system" and "Check smart cruise control system".

Forward Collision warning system continues to engage dangerously and inappropriately, almost causing me to be hit from behind, as I always leave plenty of room in front. This is very scary and very dangerous. Software updates have not remedied the situation. Hyundai motors seems completely uninterested.

My father was involved in a car crash, front end into a wall. Apparently, the front end collison warning did not sound and the auto braking system never engaged. Prior to the accident, the front end collsion warning would come on intermittently, but the dealer checked it out and stated it was working normally (San Bruno Hyundai). AFter the collision repair, the warning light comes on and the car has been at Bakersfield Hyundai now for over a week, but they can't find anything wrong with the warning system, but the system does not function (no warning of collision and auto braking does not engage). Our accident total was $10,000, lucky, no one was seriously injured.

Just quit working after being adjusted still not fixed though has been to Hyundai. Say parts are back ordered for months

I was traveling in the rain and a CHECK FORWARD SAFETY SYSTEM warning appeared on my dashboard. There was nothing in front of me to set that off. I notified the dealership and they said it was an alignment code and must have gotten hit.( Which I doubt) so wasn't covered under warranty.

Check Forward Safety System Message. Smart cruise disabled

I was driving using cruise control when suddenly I got the error message “Check Forward Safety System” and my cruise control no longer functions. Turned car off and back on and message is still there. As the emergency braking system stopped working, this is a safety issue. Have not taken it to dealer yet. The car has other software/electrical issues related to the reverse camera and Apple CarPlay. There seems to be several software issues with this car.

A warning light frequently activate to demonstrate malfunction of the driver forward collision avoidance safety features. This was presented to the dealer for warranty repair. The same defect persists despite their intervention.

While driving down the highway, a warning light stating the Forward Collision Warning system became inoperable, as well as the Adaptive Cruise Control System. Vehicle has no collisions, yet the dealer can't get the system to calibrate again.