Reversing sensors

[Fred69]

Hi.

I have a 2003 XC90 with the dreaded reversing sensor issue. Sometime they work normally and sometimes I just get a long bleep sound, even though there’s nothing behind the car. This could happen within let’s say a three point turn, for example. No rain/water needed.

I’ve had the bumper off today and have taken out all the sensors, cleaned them and blasted them with air. After reassembly I’m still getting the long bleep, randomly. I’ve read (on here) that it’s good practice to add sealant to them and my question is, to anyone that has had success in doing this, to what part do you add the sealant and what type of sealant is recommended?

I’ve (hopefully) attached an image for reference.

1 - In the tiny holes? I did notice water in these.
2 - Where the wires enter?
3 - Around the body?
Other?

Thank you in advance.

Fred.

https://www.dropbox.com/s/h2h3rt41si...%20pm.jpg?dl=0

[TruckbusUK]

Volvo generally replace both the sensors and the wiring harness if its under warranty ... so don't assume it may only be the sensors that are causing the issue.

Hope it helps.

[Fred69]

Originally Posted by TruckbusUK

Volvo generally replace both the sensors and the wiring harness if its under warranty ... so don't assume it may only be the sensors that are causing the issue.

Hope it helps.

No warranty, it’s a 2003 model. I’m not so much assuming, but eliminating. Gotta start somewhere

[gmonag]

Did you test with one removed at a time?

The problem can be with the sensors and/or the wiring. I believe water ingress is the issue.
I had the same problem and eventually fixed it permanently by renewing the wiring (genuine Volvo) and fitting four new aftermarket sensors. If you fit aftermarket, you must change them all at the same time.

[Fred69]

Originally Posted by gmonag

Did you test with one removed at a time?

The problem can be with the sensors and/or the wiring. I believe water ingress is the issue.
I had the same problem and eventually fixed it permanently by renewing the wiring (genuine Volvo) and fitting four new aftermarket sensors. If you fit aftermarket, you must change them all at the same time.

I tried testing one at a time but couldn’t get the sensors to actually work with one missing. I tried switching the button on inside but no green light appeared. As I say, it works fine sometimes. I may just get 4 new sensors as you did and see if that works.

Cheers.