acer54

RX400h Bumper Proximity Sensors issue

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I recently had my front and rear bumpers painted as there was scruff's on all 4 corners from the previous owner.

Since having them painted the sensors are going off all the time, the front ones are coming on when the car in front is about 2 metres away (before painting they worked perfectly).

Will painting effect there sensitivity or is it something else?

Is there a fuse for these that can be pulled till I get them fixed or can they be disabled or disconnected?  

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4 hours ago, acer54 said:

I recently had my front and rear bumpers painted as there was scruff's on all 4 corners from the previous owner.

Since having them painted the sensors are going off all the time, the front ones are coming on when the car in front is about 2 metres away (before painting they worked perfectly).

Will painting effect there sensitivity or is it something else?

Is there a fuse for these that can be pulled till I get them fixed or can they be disabled or disconnected?  

You can usually turn it off going through the menus.

If the bumper was painted without masking it's likely that they've got paint on them. If it was removed and then painted, possibly not put back in properly

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Done some more research and there is a button next to the rear hatch open button on the dashboard, when pushed and you here a long beep and then release it the front sensors are in fact disabled until you switch off and switch back on later - you just push the button again to disable them for that journey.

Apparently the rear sensors can be permanently switched off using a button in the luggage area which I just cannot find, anybody know where this button should be if fitted?

This is there to use if you are towing etc. to stop the sensors spuriously alarming.    

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1 hour ago, rayaans said:

You can usually turn it off going through the menus.

If the bumper was painted without masking it's likely that they've got paint on them. If it was removed and then painted, possibly not put back in properly

It was painted without masking and the sensors were painted, does this mean I need to replace them or can something be done with them?

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4 hours ago, acer54 said:

It was painted without masking and the sensors were painted, does this mean I need to replace them or can something be done with them?

I would think you'll need to replace them - I can't think of anything you could use to get the new paint off without also removing the original colour. Plus, if you didn't get rid of every last drop of paint you may get incorrect and inconsistent range-finding, possibly resulting in dings. They work by emitting ultrasonic sound waves and measuring the time for the wave to be reflected back, so a clear surface, not blocked with paint, is an absolute must.

Who paints over ultrasonic transducers? Bloody numpties!

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Actually painting sensors is very common and has no detrimental effect on them.

Possibly tho having 2 coats of paint may affect them but I suspect the coat the repairer put on the sensors hasn't taken to them. 

Take them off and use a 2 or 3000 grit paper to take that layer of paint off.

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21 minutes ago, Mr Vlad said:

Actually painting sensors is very common and has no detrimental effect on them.

Oh right, fair enough, I didn't know that - seems very counter-intuitive. I know they can be colour-matched to your car but I thought you bought them that way, rather than painting later.

As me old Granny used to say, "You learn something new every day"  :laughing:

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6 hours ago, Mr Vlad said:

Actually painting sensors is very common and has no detrimental effect on them.

Possibly tho having 2 coats of paint may affect them but I suspect the coat the repairer put on the sensors hasn't taken to them. 

Take them off and use a 2 or 3000 grit paper to take that layer of paint off.

Too much paint will cause them to react like this though

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It all depends on the type of sensor. Some have the aperture open to the ultrasonic sensor, some have a memberane to stop water ingress. The front sensors especially should have a membrane.  The open type is more common on the cheaper reversing sensors. The ones with the membrane are usually on more expensive sensors and especially need to be on front-facing ones to wether-proof them.

Under normal circumstances the membrane is transparent to untrasonic frequencies, but if it is coated with paint, it changes the properties of the membrane and it may lose that transparency and affect operation of the sensor. A decent paint shop should remove the sensors before respraying or if they can't be removed and don't need spraying, can be covered with a masking disc. If they need the sensor to be painted then you normally use masking rings to fill the gap and stop paint covering the membrane or getting into an open sensor. They can be hard plastic rings or pre-cut tape rings. If you do a Google search for parking sensor masking ring you'll see what I'm on about.

A decent paint shop should not waft paint over a bumper with sensors in situ without the sensor being masked in some way to avoid problems like this because you never know how a sensor will react when it comes into contact with paint.

 

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A decent paint shop will actually remove the sensors. All sensors are removable. 

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Does not look like you can switch off the rear sensors but as they only work in reverse it's not too much of a problem, the front ones can be turned off journey by journey so again not a problem, a valuable lesson learned if there is a next time - do not paint the sensors!

Thanks for all your input! 

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Can I ask a wee question on this topic please?

I have front sensors on my 2008 RX400H, but they do not work.  The small toggle switch under the fuel cap release is in the down position but I have tried it in the up position to no avail.  Is there a special technique inhj turning on the fron sensors (apparently an optional extra at time of purchase), or are the just gubbed (technical term)?

Burroo67

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