Hi All, This is my first post and wanted to ask if others are experiencing the same issue.

Symptom: Dynamic Radar Cruise Control (DRCC) fails to slow down the vehicle, (with slowing down or stopped vehicle in front) when DISPlay button on the steering wheel is pressed several times after DRCC is set.

The issue was tested several times with my 2015 GS350 AWD, Canadian model. Maybe it only applies to me, or perhaps it applies to all models with Lexus Dynamic Radar Cruise Control equipped.

Tests: Speed up, turn on main cruise control, and start DRCC when there's no vehicle in front, set to desired cruise speed, set the distance range control to desired range. Now, press the DISPlay button on the handle a few times (5-6, maybe flip through the whole menus, long and short presses. You are all set. Now, drive up to a stopped vehicle or moving vehicle closing to a stop (or slowing down). 4 to 5 out of 10 times, I found out that the DRCC does not sense the vehicle in front, not applying the necessary brake. The screen (where vehicle in front is pictured) shows the vehicle in front at times, other times, The sensing screen is just left blank. Still, the vehicle is on cruise mode and keeps the set speed, however the it acts like a regular cruise control, NOT the dynamic radar one when approaching a slowing down vehicle. At times, pre-collision warning beeps if the vehicle in too close, still no brake. When I says 4 to 5 out of 10 times, the other 5 to 6 out of 10 times, it works beautifully as it is suppsed to. (i.e. slowing the vehicle accordingly)

I tested several times at the 45km/h (30 miles/h), just enough to get the DRCC on, day and night, the vehicle failed to slow down in front of a slowing down vehicle (or a stopped vehicle). At times, the pre-collision warning beeps when the vehicle is at a close distance. I am suspecting that when DISPLAY button is pressed during Dynamic Radar Cruise Control is ON, DRCC fails to work as it should. Not every time, but several times.

I first experienced this at a highway moving at 100km (62 miles) and almost rear ended the vehicle in front if I didn't quicky changed the lane, and warning beep alerted.

I know I shouldn't rely on these technology and I do not, however, if this is a software issue, it should be corrected.

I've been trying to find out when exactly this issue would happen and record on my phone, but I couldn't. I was able to record one occasion on my cell phone, however, it was at night and the vehicle in front was actually a parked vehicle with the rear lights off. (although I think it should've still worked). I am still trying to come up with exact occasion for this issue and get it on video. (Speed/DRCC ON timing/AC/Lights/etc)

Did anyone experienced the same issue? or Would you try to see if you experience similar issue?

 

I've never had that issue ever. Not once and I use DRCC frequently, including pressing the display button repeatedly etc.

I wouldn't mess around, I'd go see your dealer and tell them what you've experienced. Don't use the DRCC at all in the meantime. And best not to use your phone at highway speeds to record stuff. Stay safe bud!

 

I'm new to my car but its always worked perfect (well as perfect as you can expect if you compare it to a Dodge). The nearing car ahead in the center display only shows up when there is a car in front of me. The brake lights light up (when braking) and all on that center dispaly.

Take it to the dealer for service.

 

Just bought RX 450H last week. The radar cruise control scares the heck of me. This is what happened: getting off the freeway with cruise control still on and there are cars 900 feet ahead stopped at traffic light; the car speeds up; I panicked, stepped on brakes; now here is the scary part; for two seconds, the car still accelerates while I stepped on the brake pedal, the car eventually stopped, but I could have done it smoothly if driving manually. Another situation: while at 80 miles per hour, a car cut in front of me, it took the system 2 seconds to detect and applied brakes. Again, I would have done it sooner if driving manually.

 

Haven't had that issue - use it almost daily. Sounds like a loose connection on the radar peg behind the front grille "L". I've had two connections that stopped the auto door unlock in one instance and the left BSM sensor in the other. I'd have the dealer inspect it. Don't use it for now.

Ditto.

I've noticed that the line-of-sight is pretty direct and depending on the angle the nose is pointed at in relation to the vehicle in front of me, meaning, if the vehicle in front of me is moving left or right, like on an exit ramp or a declining-radius turn, the sensor shoots beyond the car just out of my line of sight and the car quickly determines that it is free to accelerate. Those instances are very far and few but I can't say I haven't noticed that a couple times. Wrt the auot-brake in conjunction with PCS and CC, I haven't experienced a time where the PCS didn't go crazy almost instantaneously, but I'd submit that I think it calculates closure rate as a primary, meaning, if you got cut off but both of you were doing 75mph (for instance) the car would be slower to react as the CC radar would just try to slow you down more than the PCS would be trying to signal and stop you because you were approaching an object that was stopped vs your 75mph. I hope that makes sense.

 

I've had the 2013 GS for almost 4 years, and I love my DRCC. Just a few points I'd like to share:

As to the display screen with the vehicle in front, this indicates the presence of a vehicle in range of the DRSS. What is beyond that range is not taken into consideration, which explains why your car can actually be accelerating when there is a vehicle 900 feet ahead, but as soon as it does get in range, the system looks at the closure rate, and acts accordingly. It will apply braking (up to a limit) on its own, and displaying an alert if more braking is required - this is a situation where the driver can intervene to prevent the acceleration.
A similar situation occurs when someone is merging onto the highway in front of you; the merging car is visible to the driver before it comes into view of the DRSS. If that car is moving faster than you are, it will pop into view of the DRSS at a very close range. As long the distance between you and car is not -decreasing- the system sees no need to do anything...another situation where the driver can intervene to prevent an uncomfortable situation.

I have NEVER had a situation where tapping the brake has not immediately disengaged the DRSS. Sure, these systems will improve with time, and some manufacturers' systems are better than others, but I certainly do NOT regret getting it on my car - I ordered from the factory, so I got exactly the options I wanted.

 

I have a 2016... Does anyone else get a little hum when it brakes in traffic? And why does it stop so far away on a complete stop? It feels so grandpa when it does that lol. I've driven the UX, NX, and their DRCC in stop and go feel more "driver like". Thoughts?

 

The little hum is normal. And I just recently had a UX as a loaner and yes the DRCC is much more advanced & acts more human-like when in control compared to the GS. It's just a newer generation of this tech.

 

Yes. I have had the distance control go off. I have not been able to figure out the conditions under which it goes out, but I will try your situation and see if that does it. The dealer says that, because they can't replicate the problem, they can't solve it. So, if you are correct, maybe I can get them to fix it.