bayareaemt

Last weekend, my son was driving back from mountains and ended up hitting some small animal (He said it looked like fox) but since it was dark he didn't exactly recognize. Animal hit on front the bumper and got tossed back in the valley.

Since that incident now, the problem is every time I come to a full stop, there is front bumper warning in dash as of there is some object in front (with beeping sound). It doesn't show which exact sensor but there Red line in dash showing in front bumper. Sorry for lack of words in giving exact explanation. Once we start driving the beep and that alert goes away and comes again when we come to full stop at lights or STOP signs.

All of four sensors look intact in the bumper so I guess there must be something with wiring in back. Does someone know how to remove each sensor for inspection from front bumper (I see gap between bumper and front of ac condenser)? Do we have to remove front bumper to get to all sensors (if that is the case then does anyone have front bumper removal instructions, I will try Google search meanwhile)?

This is for 2015 GS350AWD Base car. Thanks in advance.

bayareaemt

I found following video link but he doesn't remove the whole bumper and he only showed just pop-up of bumper and not complete removal.



I am looking to find which way the sensor should be positioned. I can see a connector at back of sensors which are pointing up but that is for just two sensors which are in middle. I can see those through gap between bumper/grill and a reinforcement bar or something. I can't see anything about the two outer sensors and wiring from there.

bclexus

Have you tried turning the Parking Sensors Off and then On again, or disconnecting the battery for a short period of time to see if that corrects the problem?

One of the sensors may have a chip out of it or might have become scarred from contact with the road beast. I cannot imagine the wiring or connectors might be the problem with no physical damage noticeable, but stranger things have happened.

EAST

After trying what bclexus suggested, I wonder if disconnect one of the front sensors would help narrow down which sensor is affected.

At least on the 2018, the proximity sensor splits the bumper into 3 areas. Left, right, and front. If it's showing only straight lines, them it's one of the two sensors in front.


Here's how the two front ones are positioned (on a 2018).
Driver side


Passenger side

bayareaemt

@bclexus how do I disable parking sensors off and on? I did disconnect battery and reconnected with no luck. I hooked up TechStream (with help of my friend) also but it couldn't pinpoint which sensor having issue.

@EAST For my 2015, I get sections broken up in view for rear but not in front. Front is all or nothing.


something seems loose inside, because after banging bumper hard in just right of the center, problem went away for a drive today and once car ran through a pothole issue is back. :-(

ItzFilyO

I think there is a button near the rear window shade button by the center armrest to turn the parking assist on and off.

If I remember correctly, it's easier to remove the parking sensors on the pre-refresh GS bumper (2013-2015), they just clip on and off. 2016+ looks weird when I looked at it and I don't know how to remove the sensors. The 2 in the middle are clipped to a housing that is attached to the grille with double sided tape but I'm not sure about the sides. It was a little more work when I replaced my grille last time.

EAST

Ah Yea the side sensors (on a 2018) are a little different than the front. This is the only shot I have of one (this is passenger side). I didn't try to remove the sensor from the holder but I do know the holder is double side taped on as I had to replace the tape from the driver side.



OP sorry if I didn't catch it, but did you take the bumper off? If something is rattling it sounds like you'd be able to see it once the bumper is removed.

Mangsailor

My '14 has multiple sections (but it's also a lux). This, I think, is changeable in the vehicle customization menu (or carista) to swap from wide or narrow detection.

You might be able to find and change it to help troubleshoot?

EAST

Just checked live data with scanner and at least for 2018, you should be able to see output of each sensor. It's a pain to connect tech stream, else I'd check that too, but may if I have time this week. Tech steam should be able to monitor the same live data streams.

bclexus

► Slide open your center console. You'll see the Parking Assist switch to the left beside the rear shade switch. The Parking Assist switch has a P on it. You should see the green P turn Off or On on the instrument cluster.

Your problem appears to be with one of the two center-most mounted sensors since you have the center red bar displayed when it acts up.

bayareaemt

Thanks for all your help and with help of friend with Techstream, we narrowed down the issue with center-right sensor on front bumper. basically if you look at the car from front then it is second from left corner before reaching exact center-line of bumper.

another anamoly we found that the issue only happens during darker or lesser light. During broad daylight issue doesn't happen. Not sure if it has to do with temperatures outside since during day it is around 75+ plus but in evenings it drops to 55ish.

Tomorrow I am taking it to a body shop who will remove front bumper and I will try to look around what is going on with that sensor or wiring.

bclexus

I rather doubt it's the wiring. If ambient lighting affects whether it works properly I would plan on replacing that one problematic sensor because it sounds as though the problematic sensor has been damaged in some way - either internally with the ultrasonic sensor that sends out the high-frequency soundwave or its flat surface area possibly having been marred or scuffed, because it has been found that the flat surface of the sensors must be in pristine undamaged condition to work properly. Let us know how it goes...

EAST

I'm not sure if the body shop is doing it for free, but it almost seems like it might be a better use of time/money to pull bumper once you have a new sensor in hand. Else, see if you can at least leave the potentially bad sensor unplugged and still have the system partially work (at least until you get a new sensor).

If it's free (or if you are pulling it off yourself) then yea, poke around and mess with the wiring.

At the end of the day, I hope it is solvable via fixing the wiring or tapping/cleaning the sensor.

bayareaemt

Body shop friend will do it for a beer and burrito. I called local lexus dealer and they didn't have sensor in stock (don't want to put aftermarket). Dealer said it will arrive on Monday so I am taking a chance at friend's body shop tomorrow. He might have buff some scuffs out on that bumper as well where animal did hit. If wiring is found loose or sensor came of mount then we will just try to put double-sided tape to mount properly. Sensor from front doesn't show any sign of scratches or damage on front surface.

bayareaemt

If I press the sensor from front, I can feel that it is going inwards be 2-3 mm. Other sensors don't.

Maybe when I press the brake to come to a stop, that movement is causing the issue.