CYBEX CALLISTO Complaints

I purchased my CYBEX Callisto G 360 on April 26, 2025. The harness does not stay tight: after I pull the adjuster strap to tighten it and let go, I can pull on the shoulder straps and they loosen again without pressing the harness release button. I’m concerned the harness adjuster is not holding the restraint securely, so I have stopped using the seat. It's extremely dangerous for this component to be failing.

My child was in the car seat and I noticed that the harness was not staying tight. I did research and apparently if a small object and or crumbs gets stuck under the fastener the harness won’t lock in place. I reached out to the manufacturer and they failed to do anything about this. They have no warnings regarding it and did not want to replace it. Something must be down, if this is happening on mine it is happening to many others.

Failed Component: The SensorSafe chest clip mechanism on my CYBEX Callisto G 360 convertible car seat experienced a primary mechanical binding failure. The clip physically sticks and jams during buckling and release operations. The unit is currently in my possession. Safety Risk: The mechanical failure prevents smooth securement and unbuckling of the harness. A sticking or jammed chest clip creates a severe safety hazard during daily use and presents an extreme danger of delay during emergency extraction of my child from the vehicle. Inspection History: The seat has not been physically inspected by police or insurance. I have provided detailed video evidence of the mechanical failure directly to the manufacturer (CYBEX) under support ticket Case #679809. The manufacturer acknowledged the defect by offering a replacement chest clip component, but declined a full-unit replacement. Once you submit this, keep the confirmation number or NHTSA Complaint ID handy—you can send that ID number directly to CYBEX as proof that a formal federal safety report has been logged.

While adjusting and testing the five-point harness on my Cybex Callisto G 360 SenSa child restraint, I observed that the harness did not maintain tension after being tightened. As demonstrated in the attached video, the harness loosens with minimal force without intentionally actuating the harness release. This raises concern that the child may not remain properly restrained during vehicle operation or a crash. I immediately discontinued use of the seat because I no longer consider it safe. I have contacted Cybex requesting a warranty replacement and am submitting this report because I believe this may represent a safety-related defect requiring investigation.

After purchasing this car seat directly from Cybex and using it for approximately one year, I noticed one day that the harness straps were loose when I took my toddler out of the car seat. I then discovered that the harness locking mechanism was not functioning properly. After tightening the harness, the harness adjuster would not lock securely, and I was able to pull the shoulder straps loose without pressing the harness release mechanism. This created a significant safety risk because the harness could not reliably maintain the tightened position necessary to properly restrain my child. If the issue had not been noticed and we had continued using the car seat, the harness could have loosened during normal use or a crash, potentially allowing excessive movement of my child and reducing the effectiveness of the car seat's restraint system. I immediately stopped using the car seat and reported the issue directly to Cybex. They approved a replacement car seat and provided an upgraded model. Cybex did not request that I return the original car seat for inspection or testing. During a subsequent conversation with a Cybex representative, I was told that Cybex had received numerous complaints involving the same issue with the harness locking mechanism. I was also told that the company had made design modifications to newer models to address the issue. My understanding from the representative was that Cybex did not need my particular car seat returned for further testing because of the other reports they had received. The original car seat is no longer available for inspection.

The back anchor tether strap will not tighten past a point anymore, making the car seat easily to move. If I was to get in a wreck, this could seriously cause injury to my child. We have watched countless videos and read instructions on how to install this properly and still having issues. I have reached out to the manufacturer. They were supposed to send me a shortening tether clip that they stated “may work”. At this point, I have not received the other clip and my child safety is at risk as I am driving every day.

My child does not eat in his car seat. Every day debris dust etc gets under the release mechanism button causing the harness straps to randomly loosen. Huge safety issue that could lead to a fatal accident. Cybex’s solution is to tell you to clean out the mechanism but there’s no telling when or where the straps will stop tightening again. It’s not feasible to clean the strap every time I use the seat. My son’s straps fully loosen just by him leaning forward. This seat needs to be recalled!!!

After tightening the harness, the straps slip and loosen completely on their own without pressing the release button. This happens due to normal movement while driving, leaving my child completely unrestrained and unprotected. I have already followed the manufacturer guidelines to thoroughly clean the adjuster mechanism and the strap area with warm water to rule out any debris or buildup. While it seems to hold for a brief period, the mechanical failure returns after a couple of days.

Harness button gets everyday dirt and debris lodged under the release mechanism causing the harness to not tighten. My son’s straps randomly loosened. He does not eat in his car seat but the slit in the seat cover is in the perfect position for things to fall straight into the release buckle. Very dangerous.

Harness straps are becoming loose due to debris getting lodged in the release tension button causing straps to loosen without pressing button causing a safety concern. Cybex’s solution to this is to basically tell you to just keep it clean when they should be recalling and fixing this issue with a cover to prevent this (which they have done with the newest version coming out the T) nuna recalled their rava for this issue and it’s time for cybex to as well.