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Dear fellow contributors!

A couple of days ago I put my car into reverse, and the rear right parking sensor started beeping incessantly, trying very hard to convince me that I was about to collide with an obstacle. Nothing was showing on the rear camera screen, but I got our nevertheless and verified that nothing was in my way.

Odd I thought.

Later that day, again I put the car in reverse and this time BOTH the right and left parking sensors started beeping madly at me. Again, no obstacle.

The problem persists, to the point that I have now disabled the parking sensors, solely relying on the reversing camera.

Any idea or suggestion before I make contact with my friendly dealer?

Thank you.

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Have you tried give the sensors a clean then re-test?

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The front parking sensors on my RX 400 were aftermarket ones and sometimes when it's been raining they give false readings because of the wet I guess. I turn them off if that happens and then activate them at a later date . seems to do the trick

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As mentioned above, turn the sensors off, give them a clean and then turn them on to see if it goes away

if not, its like you have a faulty sensor. Shouldn't be too costly at all if it needs doing.

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Check the wiring is sound?

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Having the same problem with the front sensors on our RX450h. Started a couple of months ago when it was raining. The sensors would initially go off if you were near an object as normal but then would constantly go off when nothing was in front. It's been back to Lexus twice but they couldn't find anything wrong and in all fairness it has been fine up until the last week where it has been irratic again. I have cleaned the sensors but that has made no difference. Slightly disappointed that this has been an issue. Back to Lexus it is.

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I have cleaned the sensors. I don't think it's related to a faulty sensor as the display shows alerts for both rear corners.

Wiring? Maybe... Interesting that, as for F.A. the problem started when it was raining. Maybe water is getting in somewhere.

Car is booked in end of next week... Will report back...

Thanks for the various suggestions.

Sent from my D5803 using Tapatalk

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Demonstrating the problem was an issue for us as it only happens under specific conditions which typically are never present when going to the dealer. I took a video of the problem and Bristol have suggested that should it happen again, then they will probably change all the sensors. Good job it's still under warranty but did not expect electrical issues with a Lexus

Sent from my Iphone using Tapatalk

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Never had any sensor problems = only things that set it off is seriously heavy fog last week and snow.

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I am hoping that my dealer will readily identify the fault on the basis that it is permanent rather than intermittent. I'll make sure to get them to explain what it was and how it was sorted so that I can report back.

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Not having these sensors, I don't know how they are fitted or the wiring is run.

It is extremely (in my opinion) unlikely the ultrasonic sensors themselves are faulty - they either work or don't when made at the factory.

If it were me, I'd spend the time to check all the obvious things first:

1) Unplug each sensor, by popping it out of the bumper - I imagine each one has a plastic connector/plug, and use di-electric grease on the plug after checking/cleaning any corrosion found.

2) silicon spray each sensor - this will keep moisture off and allow water to bead off them and not let water soak into them if that's at all possible, then re-install/push back into bumper.

3) Find the unit where the wires to the sensors runs back to, unplug them at this end and clean the plug/connector and apply di-electric grease.

Whilst doing the above, you may find an obvious big problem (like the sensor control box full of water or damaged wiring) either way, ruling the basics out can't hurt and will save you cash if it has to go into the dealer as you can tell them what you've done and/or found. Remember, an hour of tech time is £100 or more!

Also, one other idea, if you have one sensor playing up, why not swap it over with a working one? If the fault follows the sensor then bingo!

If the fault doesn't follow the sensor then most likely wiring or sensor controller issue...

Let us know how you get on & good luck!

Chris

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Thanks Chris. I will be taking the car to the dealer as it is still under warranty... let them do the hard work! ;-)

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Update...

Here is what was explained to me as a possible - but not definitive - cause of my problems. I am saying possible, as diagnostics did not pick up any fault. I hope I will do the technician justice in my explanation below!

.

The sensors are made of three main parts. An outer ring, a small disc (the sensor), and in between a rubber ring. The sensor works in a way that similar to a sonar, sending and receiving sound waves. The rubber ring around it allows the sensor to register the tiny vibrations from incoming sound waves. When the 3G glass coat (clear coat protection) was applied to my car, it was also applied over the sensors and surrounding rubber ring. Over time, the 3G glass coat hardened to such an extent that the rubber ring became completely rigid, thus preventing any kind of movement., hence confusing the system.

The sensors were removed, dismantled and thoroughly cleaned so as to remove all trace of the clear coat, and then re-installed.

No problem since.

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