Rear parking sensor failed without error

[Acer]

Hi All,
It appears the driver side rear sensors stopped working and the mrs has cracked a light. No errors at all and says rear parking sensor active.

Is this normal and how much to fix? Appears that the two on that side work occasionally and so presumably it is just a case of swapping those sensors and then getting a replacement light cover?

[cassell]

Are you sure she's being honest with you about the cracked light by blaming the sensors!

Usually if a sensor fails it triggers a 'park assist service required' message and all four sensors become 'dead'. If the 'park assist active' message is visible when you engage reverse gear then all four sensors are usually working.

If you do find that any sensors have failed or fail occasionally, replace them with genuine Volvo ones which are around £60 each and avoid the £13.99 ones off ebay -"buy cheap = buy twice" usually!

Finally, check that the left rear radio speaker hasn't been turned down/off with the sound system controls as that's where the bleeping sound comes from!

Hope this helps!

[Acer]

Are you sure she's being honest with you about the cracked light by blaming the sensors!

Usually if a sensor fails it triggers a 'park assist service required' message and all four sensors become 'dead'. If the 'park assist active' message is visible when you engage reverse gear then all four sensors are usually working.

If you do find that any sensors have failed or fail occasionally, replace them with genuine Volvo ones which are around £60 each and avoid the £13.99 ones off ebay -"buy cheap = buy twice" usually!

Finally, check that the left rear radio speaker hasn't been turned down/off with the sound system controls as that's where the bleeping sound comes from!

Hope this helps!

Hi, I tested the rear driver side two sensors myself and they do seem dead, but both seemed to work intermittently when i waved my hand over them. Is it only out the left speaker that sound is emitted for all sensors?

Does seem odd we get no error but the left hand side are definitely working at the moment. That left me thinking it must be the sensors, but why would two become faulty at the same time.

[ifzal123]

Three of my parking sensors failed. I did not get any error messages. Just got a constant beep when reverse was selected.

Once replaced all was good. The cost was covered under warranty

[Acer]

Three of my parking sensors failed. I did not get any error messages. Just got a constant beep when reverse was selected.

Once replaced all was good. The cost was covered under warranty

At least you got a bleep! It is pretty out of order they can fail in such a way as to intermittently work but flag no error. I thought the first bit of trouble and the system is supposed to take them all down and flag an error. Of course Volvo won't be interested as the vehicle is well outside warranty. Never mind the fact this failure will cost me a brand new light cover and smart repair to the paint work, not to mention the sensor cost. Not happy!

Another weird observation. As I drove it to the mechanics (in drive not reverse of course :)) I got a couple of random beeps and then nothing.

[ifzal123]

totally agree with you. For a 4x4 that is a luxury vehicle it is disappointing to say the least considering how many separate systems there are and the simple things have been missed. But that's how the dealers intended on making their money so that you have to get the car diagnosed to identify the problem.

[Acer]

Hi All,
Seeing as the motor is over nine years old, if it turns out to be a bad sensor, would it be better replacing all four at the same time?

[ifzal123]

yes agree. since the bumper has to be removed.

All mine were changed. The 3 faulty ones were changed but then only worked intermittently. Then the remainder were also changed and all was good.

Clan mentioned that Volvo sell a kit which is cheaper than buying sensors individually. He also mentioned that in some cases it is best to change the wiring loom which comes as part of the kit

[12345]

Volvo stopped selling the kit, or at least it's not cheaper than buying the 4 sensors anymore. They probably realised they could make more money if people brought individual sensors.

My advice is also to buy a new loom while you have the bumper off. I replaced 4 sensors and when it's damp I still get random beeps. It's a regonised problem some looms don't like the damp. It's only £30. A bargain compared to 4 bloody new sensors !!!

[Acer]

Volvo stopped selling the kit, or at least it's not cheaper than buying the 4 sensors anymore. They probably realised they could make more money if people brought individual sensors.

My advice is also to buy a new loom while you have the bumper off. I replaced 4 sensors and when it's damp I still get random beeps. It's a regonised problem some looms don't like the damp. It's only £30. A bargain compared to 4 bloody new sensors !!!

My local garage tried reading the code but no joy. They say only Volvo will be able to do it. What are the chances of this being the ECU when two of them work fine? Am i on safe ground asking the local garage to just go ahead and do all four plus the loom?

[12345]

The way I looked at it was, Volvo we're going to charge me £100 just to tell me what's wrong. And then the cost of parts and £100 + per hour to remove the bumper. I guessed in the best outcome was going to be approx £250 for 1 sensor. I brought 4 sensors for £260 and fitted them my self. It was very easy to do. It would be annoying to pay to replace some of the sensors, and then to pay out again if the remaining broke a few months down the line if you were to get Volvo to replace what's faulty currently.

[Acer]

The way I looked at it was, Volvo we're going to charge me £100 just to tell me what's wrong. And then the cost of parts and £100 + per hour to remove the bumper. I guessed in the best outcome was going to be approx £250 for 1 sensor. I brought 4 sensors for £260 and fitted them my self. It was very easy to do. It would be annoying to pay to replace some of the sensors, and then to pay out again if the remaining broke a few months down the line if you were to get Volvo to replace what's faulty currently.

What was required to replace them. Is it easy enough taking the bumper off?

[12345]

Yes it's easy there's a good guide on here how to remove the bumper. Basically about 6 screws and 4 bolts. And the sensors unclip off the bumper. No more than an hours time.

[Acer]

My local garage tried reading the code but no joy. They say only Volvo will be able to do it. What are the chances of this being the ECU when two of them work fine? Am i on safe ground asking the local garage to just go ahead and do all four plus the loom?

Not sure whether to be worried or happy. Volvo read the code, found it was number 3 playing up, reset the system and now it works. Error cleared. Should i insist it is changed anyway?

[12345]

Not sure whether to be worried or happy. Volvo read the code, found it was number 3 playing up, reset the system and now it works. Error cleared. Should i insist it is changed anyway?

I would leave it and see. There's no point paying out if it's ok. Good luck