PreCollision OFF indicator came on with Lane Departure icon orange

Hi y'all,

I was sitting in my 2021 4Runner nightshade for about 20 min with the engine idling while on a work call (not sure it's relevant, but it was about 105 degrees outside). I backed out of the parking spot and put it in drive. While still in the parking lot, I noticed that the Orange Pre Collision OFF indicator had come on, along with the light for Lane Departure . . . I leave Lane Departure off, so that light is not usually lit, but if I turn it on, it is green. My traction control light was not on...just the 2 orange lights (pre-collision OFF, and Lane Departure).

I pulled over and could not find the culprit, but it self-resolved, but of course, I'm not satisfied to just ignore this. I know that turning off the traction control (pressing the overhead button, or holding it for 3 sec to turn off a couple of features) will deactivate the pre-collision, but that would also illuminate the traction control orange light, but it was not on.

I have been unable to reproduce the issue, and when I took it to the dealer, the service advisor seemed less than knowledgeable (first thought I was getting an alert of being about to hit something, then after I explained again, she thought that it could be a glare that caused the warning to sound . . . I explained a 3rd time that there was no crash-alert. . . just that the light indicating that this system was off. She then thought it might be the sensors, even though the pre-collision is a camera/laser thing, not bumper sensors). I cannot get in for an appointment till later next week, and have found that quite often, forum members seem to understand these issues better and steer me in the right direction to then steer the advisors towards, so they can get the techs to look in the right places for the issue).

Any idea why this could've happened? Could the heat have played a role in this? My 4runner was in the sun for about an hour before I put it in gear.

Thanks y'all
Jon

 

just found this video . . it is about a Camary, but the idea seems to be the same thing. Basically, heat can screw with it:
https://www.youtube.com/watch?v=xFEXyOwjyk8

 

Did you bump any switches while getting started up? I ask because yesterday was doing roughly the same thing, and I noticed after pulling away that the indicator for my rear locker was flashing red. I tried a couple things that didn't resolve it, so as a last resort, I pushed the locker switch, which turned it off. I must have bumped it while I was removing my windshield reflector.

 

I had wondered about that, but my sunscreen can't really get up into the overhead (where the overhead lights are) recessed Traction Control switch to press it . . . and had I pressed that, there would be another orange indicator showing that Traction Control was off. I think it was the heat issue (see the video above your reply).

 

It happens to me somewhat frequently. I think it is the sensor overheating or being blown out due to too much glare or light. Seems to happen mostly when idling at one location and generally facing the sun and only in summertime. It has always resolved itself in ten minutes or so after you move. I think it is the camera sensor at the top center of the windshield, but in reality, it may be a combination of sensors.

I think it has happened to me 3 or 4 times this summer but, I'm parked with the engine idling in the sun every week day.

 

It is your TSS sensor the square thing on the front bumper. It does not like dirt, snow, extreme heat, and heavy rain. It is mentioned in the manual. It tells you if the warning light comes on, the sensor needs to be clean. It will reset itself in several minutes. There is no way around it. I just deal with it. It is a design flaw and there is no malfunction.

 

this happened to me on saturday. was driving back from lewes, delaware and got into some heavy rain. that light came on then a warning that the pre-collision sensors were disabled about 10 minutes after the light lit. once the rain stopped light when out.

 

That happened to me too a few days ago when it was really hot shortly after leaving work. I couldn’t use radar cruise so I has to switch to regular cruise control. After 5 min of driving it came back to normal and I was able to use radar cruise

 

Had the same thing when the sensor got covered in thin layer of snow. Once I wiped it off it was back to normal.