red triangle/exclamation point and icon on screen

you're right.. it's the headlight leveling sensor. the sensor on the rear axle of the car will rust out..

 

I think that you will need 89408-47010. MSRP is $347, you can buy it for $264 plus shipping here:
Champion ToyotaWorld

You can also try removing the old part, to see whether you can disassemble it and clean off the corrosion. If so, maybe you can save the $$$ associated with the new part.

 

Hi Matt,

I don't have personal experience with this since I haven't had to replace that level sensor yet. However, allow me to suggest what I would do: Disconnect the 12V battery negative cable first. Then raise up the rear of the car on jackstands, crawl under the car, find the sensor on the driver's side of the rear beam axle, remove it, and replace with the new part. Lower the car back down, then reconnect the battery.

See if the headlight aim is OK. If yes, then you are done. If no, then you might have to ask for dealer help but at least you bought the part at a discount and hopefully the labor charge will be reduced.

Good luck.

 

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Yes, the reason to disconnect the 12V battery is that the headlight beam level control ECU receives 12V power at all times via the 10A GAUGE fuse. While you are deinstalling and installing the sensor, if the car remains powered up then you might be inputing out-of-range signals to the ECU that would confuse it and necessitate the reset using the Toyota diagnostic laptop.

Anyway, let us know what happens after you've replaced the part. Good luck.

 

The Dealer replaced my part for only the labor. I think this is a known problem but only will rplace when it fails. This was on my 2005 Prius. I now have a 2010 Prius.

 

I have this problem too. Why can't we just re-level the headlights to where we want them and go on with driving like other cars? Is this possible?

 

Did you ever get this figured out? I've been having the same problem with my 2004 prius and I want to pay/labor as little as possible just to get the red ! out of my face! I see that there are headlight leveling sensors on ebay for under 50 bucks. Does anyone know if that's all that needs to be replaced?

 

I just posted on a similar thread: red ! triangle and yellow headlight symbol | PriusChat

I would be careful of getting something off ebay unless you know it is the right part. Search the web for Prius height sensor unless the ebay picture is obviously the correct part. $50 is really cheap and if it isn't corroded would be a good deal.

 

This is an old question but was previously unanswered. Since this thread was resurrected, I'll answer it now.

The point of having the HID headlights level sensor is that as weight is added or removed from the rear of the car which causes the headlights to move up and down, the sensor will provide info to the headlight computer to automatically adjust the aim accordingly. HID headlights are brighter than halogen, and Toyota engineers felt the need to include this auto level feature into their design.

If you re-level the headlights without fixing the problem, then to the extent that you add or remove weight from the back hatch or rear seat, the headlight aim will be off. If the aim is high then you will irritate oncoming traffic. If low then it will be hard for you to see.