I've had this problem with my reversing sensors since about last September.

Sometimes they work fine, sometimes they don't. These days mostly they don't.

When they don't work, the display shows them both flashing and beeping with varying degrees of proximity, even with nothing behind the car.

I took the bumper off in December and checked them all, all wiring looked good.

The only time they seem to work now is after a long drive.

I wonder about dampness or corrosion somewhere.

Does anyone have any suggestions where I should try looking.

 

Thanks,

Try giving them a bloody good clean, I had very light overspray on mine which caused a problem.

I wish it was that easy!

When  I took the rear bumper off in December, I took each of the sensors out, cleaned them, tested their resistance (all similar), put it all back together - same problem - not working.

But the next day they decided to work.

I have read about the reversing switch and wondered if it might be corroded/damp. Can anyone advise where/what it is?

 

Thanks,

@Regsmyth

Checking their resistance is pointless as they are a digitally activated component.

 

Have you checked they all emit ultrasound clicks?

 

Mine too are temperamental and all I can suggest is keeping them clean to mitigate false reading.

 

If your car's are original 14 years old it's likely just age and need replacing.

Try module in boot left hand side I think , hose comes off rear windscreen wiper and spray's module

Thanks all, I'm still not sure.

 

Yes all the sensors are clicking (even when the display is flashing and erratic).

Tonight the system was working perfectly, after driving around town for a couple of hours. First time for several days or perhaps weeks.

 

When I had the bumper off in December I had access to the module, and it all looked fine, wiring and connections good. The rear washer pipe is disconnected at the front, so not the culprit.

I noticed some water below the battery. Not sure how it's getting there, but my thoughts were maybe there's some damp somewhere at the front which is affecting the system, and after some driving the heat dries it out and the system works again. I can't really explain it otherwise, but i'll keep on hoping for that eureka moment.

I had everything off and out, cleaned connectors, sensors and dried everything out over night but still the same. Gave the sensors a T cut and they have worked for about the last year with no problems and I had the same or very similar issues - just saying as I know sometimes we can get into holes looking for things, just like I did. 

Edited 19 March, 20224 yr by Morph

Ok thanks all.

Still working after 3 days.

I'll be keeping an open mind until the fault becomes permanent or correlations become clearer.