BMW X5 (05 Reg). Question about possibly faulty parking sensors.

bobbentos

Hi all

Firstly, thanks to the guys who commented on my previous post (faulty Park Lights). That problem is sorted now thanks to those guys.

Because of that brilliant advice I'm gonna see if anyone can help me again with this problem.

As stated I have a 05 BMW X5. For no reason about 3 weeks ago the parking sensors started acting strange. Here's the problem...

For the past 7 months (since I have had the car) I haven't really took much notice of the parking sensors. I just took them for granted. I'm sure that when I approach an object at the FRONT of my car the warning sound comes from the FRONT of the dash. Similarly, when I am reversing and getting close to an object at my rear the warning sound seems to come from the REAR of the car. I'm sure this is how they are supposed to work and indeed they worked fine for ages.

All this was OK until recently...

For the sake of ease of explanation, please imagine I'm in a completely empty field (so people don't assume false objects etc could be triggering the problem).

Problem...

As soon as I put the car in REVERSE, the parking sensor light (on the centre console near the other buttons) goes mental and flashes and the warning sound starts beeping from the FRONT of the car. Even though the car is REVERSING the warning sound comes from the FRONT??? !!!!!!?? But alas, I am in an empty space, so how could ANYTHING be triggering ANY of the sensors? There should be no noise or flashing button!

So, imagine I am now in a built up area. The parking sensors just don't work. It's the same story when I put it in reverse (Sound from the front, flashing button etc). When I drive close to something at the front they don't work. Same with reversing.

So, by coincidence, yesterday, I had the Plastic Wheel arch replaced (because a few months ago I had damaged it on a high kerb). When I went to collect the car the garage had washed the car. Lo and behold, when I drove away the parking sensors were working properly again! So, I assumed that one of the sensors was dirty and the wash by the Garage had cleared it. However, just now they've gone faulty again with the same fault.

As it stands now, none of the sensors actually work and the problem with the Sound coming from the FRONT when I reverse is back again.

With regard to the bit about the field etc I am just trying to make it clear that the problem actually occurs when there are NO obstructions anywhere (ie empty field for example).

Any advice guys???

Thanx

vikingaero

I had a problem with the front parking sensors on our Zafira. Turned out it was a simple broken wire which the auto electrician replaced and resoldered. On this sensor system, once there is a fault it knocked out all the other sensors.

johnnyroper

the parking sensors on the front and rear are turned on when reverse is selected.

if you are getting false warnings when nothing is around then you have got at least 1 faulty sensor,if you get it plugged in BMW can pinpoint which sensor is duff.You can sometimes find out which one is faulty by turning them on and having a listen to the sensor you should hear lots of clicking from them,sometimes when failed the noise stops.
i had the same on my x3 a few years back although i got lucky and found a full set of sensors on ebay for £50 which was cheaper than bmw diag let alone the £100 ish per sensor BMW parts charge.

also on a x3 they were easy to fit as bumper pops off easy not sure if this is the case on x5,the bumper was also non painted so sensors did not need paint either.

just re read post i would bet the parking sensor nearest the damaged arch is at fault due to the shock of impact.

petrolhead69

bmw parking sensors are prone to water ingress causing the system to sense a fault and disable the sensors and bleep to warn of the fault. You can find out which one with a diagnostic lead, an £8 ftdi vagcom lead with the two k lines shorted together works well using inpa software. the other way to diagnose which one is causing the problem is activate the sensors, then go round and put your ear up to each of the sensors and listen for a faint rapid ticking, the sensor not ticking is the faulty as johnny said. there are about 5 different bmw parking sensors so you need to remove it to get the number. bmw wanted £116 for 1 sensor but brand new genuine bmw ones from a bmw main dealers ebay shop are £35 so that shows you bmw think of their customers, they think were just here to be gouged at every oppertunity.

somech

very common fault on bmw's at this age

there is a no cost diagnostic to identify which sensor is duff

turn on ignition select reverse hold your finger on each sensor you will hear/feel a clicking no clicking = duff sensor

bobbentos

Thanks to Vikingaero, Johhnyroper, Petrolhead69 & Somech. Fantastic advice again guys! I had the car booked in for tommorow. It's a friends Garage so he wouldn't have charged me loads but I'm estimating £50 labour and the cost of some 'Original' parts. I am astounded at the level of knowledge you guys have.

Indeed, I went out to the car. Put it in reverse, all sensors were clicking. Put it in drive front Offside not clicking. Others were! So, thanks to you guys I have found the faulty one. Next question. How hard are they to fit? I'm pretty competant and capable so if they are easilly accesable that should be no problem. Am gonna buy one of the ebay store like you petrolhead suggested. Just need to know how to remove it now.

Thanks again guys. Brilliant advice.

PS. My mate rang me up last night and said "Did you get that problem sorted with your parking sensors because mine in my X5 have just started playing up too"!

bobbentos

Hi guys

When I said I was pretty competant, after reading a few forums it's clear that it's a case of Front Bumper off (Front corner sensor).
How easy/hard is this? What damage could I cause?

somech

bruised knuckles chipped and scratched paint are possible but it is doable if you have a bit of common sense and some decent tools.

as for knowledge many years as vehicle technicians helps
also check out bmw car magazine forums some helpfull guys full of knowledge

johnnyroper

You can also cut the sensor surround to enable the sensor to be changed without removing bumper.
It will mean changing the surround aswell as sensor but is far easier,I was advised to do this on the BMW forum when i used to have the x3