jfs1969
Posts: 1
Joined: Sun Oct 24, 2021 3:46 am

Re: Replace rear parking sensor

Thanks all above for posting very helpful. I'll add my experience in case of use to anyone, it was easier than I thought it would be ;-).
Girlfriend complained of intermittent false signals from parking sensors on her 2017 i3. I had a look and two of the 4 rear sensors were corroded, paint intact but bubbling.
Thought I might as well replace all of them as probably the other two would go one day. BMW Brighton quoted £580 to replace all 4 sensors. £300 parts plus £180 labour.
I had a look on ebay and you can get aftermarket ones for £10 each and ones from Valeo, who are the OEM supplier, were £25 each. I was pretty confident these would be fine but slightly worried about doing the job myself as I'm a somewhat reluctant mechanic. I once changed a rear sensor on an Audi A1 and the back panel didn't go back on very tidily, leaving uneven panel gaps. But I saw the video above and, crucially, the comments that you don't need to take the whole panel off so gave it a go.
  • Tools - 8mm spanner - that's all you need!
  • Undo the ~5 self tappers along the bottom of the rear panel. Also remove the plastic bash plate it screws into to give yourself a bit easier access, another 4 or 5 self tappers.
  • With one hand behind panel gently pushing the tabs on the sensor apart, and the other hand gently pushing the sensor from the front, they pop out easily.
  • Disconnect from cable.
  • Remove the rubber seal from old sensor and fit it to the new one.
  • Push the connector on. It only goes on one way or at least will only click in one way.
  • Press back into its hole making sure seal is not pinched and the sensor is flush.
  • Repeat for the others.
  • Get into car and check they are working.
  • Refit the bash plate and screws for the rear panel.
It took me one hour in my slow and steady way. I can't believe it would take a competent mechanic more than half an hour. I don't know BMW Brighton's hourly rate but they are probably charging 2 hours for this job which is a piss take.
coachark
Posts: 2
Joined: Sun Feb 06, 2022 5:34 pm

Re: Replace rear parking sensor

1.) How did you all pinpoint which sensor was faulty? I am getting a failure message but no indication as to which of the four is inoperative.

2.) Does anyone have a link to a sensor that they know works? I’ve only been able to find them for $150+.

Thank you.
flyboy320
Posts: 37
Joined: Sat Jun 02, 2018 5:38 pm

Re: Replace rear parking sensor

coachark wrote: Sun Feb 06, 2022 5:40 pm 1.) How did you all pinpoint which sensor was faulty? I am getting a failure message but no indication as to which of the four is inoperative.

2.) Does anyone have a link to a sensor that they know works? I’ve only been able to find them for $150+.

Thank you.
I had ones that went bad due to paint deterioration on the face of the sensor so it was easy to tell which ones were giving the error. I ordered cheap Amazon ones and they worked great;

https://www.amazon.ca/gp/product/B07SWJ ... UTF8&psc=1
coachark
Posts: 2
Joined: Sun Feb 06, 2022 5:34 pm

Re: Replace rear parking sensor

flyboy320 wrote: Mon Feb 07, 2022 5:42 am
coachark wrote: Sun Feb 06, 2022 5:40 pm 1.) How did you all pinpoint which sensor was faulty? I am getting a failure message but no indication as to which of the four is inoperative.

2.) Does anyone have a link to a sensor that they know works? I’ve only been able to find them for $150+.

Thank you.
I had ones that went bad due to paint deterioration on the face of the sensor so it was easy to tell which ones were giving the error. I ordered cheap Amazon ones and they worked great;

https://www.amazon.ca/gp/product/B07SWJ ... UTF8&psc=1
Thank you for the link. My paint is all intact so unfortunately I’ll have to come up with another way to troubleshoot. At $15 per unit I would just order four sensors but unfortunately they only have one left in stock.
bazza2000
Posts: 1
Joined: Sat Nov 05, 2022 4:00 pm

Re: Replace rear parking sensor

Just wanted to post a thankyou for the procedure. I picked up a replacement sensor (original corroded) for £22 and then followed the procedure earlier in the thread. Its as simple as removing a few screws and popping in the replacement. I didn't even need to jack the car up, there was enough clearance for me to get my head under the bumper and flex it enough to replace the sensor. Just saved me £280 the local BMW specialist wanted to charge me. Took me about 20 mins. Thanks again.

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