DIY Front Parking sensor repair

[Hkbruin]

So I had the unfortunate luck of hitting tire debris on Friday morning driving down the freeway, and the rubber chunk the size of a golf ball hit my bumper just to the left of my front passenger side parking sensor. I immediate was warned by the system on my dash that the sensor was obstructed or needed to be cleaned. After reaching the new Carlsbad, CA service center near my office, I parked my car and saw that the parking sensor was pushed in, with the sensor and sensor bracket both intact but hanging inside the bumper. My warranty had just lapsed as I surpassed 50k miles, but the service center said the repair wouldn’t be covered anyway. They couldn’t accommodate my same day drive-in understandably. So they scheduled me for 3/10.
Well, being the impatient person I am and not wanting to drive my family around with the parking sensors and assists disabled, I searched online for previous repair resources and guides.
I couldn’t really find on the parking sensor fix however there are a few good YouTube video detailing the frunk and bumper removal.
Long story short, you don’t need to remove the front bumper to replace/reseat the right front (closer to the license plate) by removing the frunk and then reaching in a triangular opening to reach the sensor.
It’s actually easier to remove the sensor from the harness and then repair the bracket with strong double-sided adhesive or a permanent epoxy glue. Once the bracket and sensor are snuggly put back, plugging in the harness is a simple click. Granted, you’ll be doing some of the work without being able to visually see what you are doing, but the process is simple and only takes all of 30 minutes to repair.

I probably saved at least $175 labor charge and possibly some other bogus up sell for a new sensor, so I am pretty happy that I was able to do it within a very short amount of time, and with a 10mm socket wrench and some really strong double sided tape. If I see it coming off, I will use the epoxy glue next time. Since my warranty is done, it seemed like a simple fix for anyone to do

 

[Akikiki]

Hmmm, the old tricky click trick, said Maxwell Smart.

 

[Mr. Frodo]

Do you know if this would have been repaired under warranty? My parking sensor popped into my bumper as well.

 

[Hkbruin]

Not sure, but I don’t think it would be covered as there might be a broken bracket they charger for, or even a faulty sensor, which could be costly.

 

[Hkbruin]

Forgot to update about the repair job: the double-sided tape did not hold for longer than a couple days after it started raining and temperature fluctuations caused the piece to come off. I ended up using a two-part epoxy glue and it hasn’t come off since.

 

[Mr. Frodo]

Forgot to update about the repair job: the double-sided tape did not hold for longer than a couple days after it started raining and temperature fluctuations caused the piece to come off. I ended up using a two-part epoxy glue and it hasn’t come off since.

Thanks for your input!

 

[ChaoticNeutral]

Not sure what happened to my sensor, but it’s dangling inside the bumper. Still warrantied but I won’t know if they are gonna cover it until next week. Thank you for posting this information, at least I can do a DIY fix instead of paying the $300 estimate they’ve sent!

 

[Chopr147]

Thanks for the write-up. I am fixing mine next week and assumed I would be removing the bumper. I'll try this first. Same thing happened to me. Tire debris struck the front bumper knocking the sensor inside the bumper. I can feel the sensor and clip which appears to be intact. I have spent all Winter with the "parking assist" warning every time I slow down to about 5 mph.

 

[Peter Simpson]

Thanks for the write-up. I am fixing mine next week and assumed I would be removing the bumper. I'll try this first. Same thing happened to me. Tire debris struck the front bumper knocking the sensor inside the bumper. I can feel the sensor and clip which appears to be intact. I have spent all Winter with the "parking assist" warning every time I slow down to about 5 mph.

Were you able to fix yours? How did it go? I have a sensor that needs to be re-seated right now on a 2022 M3

 

[BoulderP85D]

So I had the unfortunate luck of hitting tire debris on Friday morning driving down the freeway, and the rubber chunk the size of a golf ball hit my bumper just to the left of my front passenger side parking sensor. I immediate was warned by the system on my dash that the sensor was obstructed or needed to be cleaned. After reaching the new Carlsbad, CA service center near my office, I parked my car and saw that the parking sensor was pushed in, with the sensor and sensor bracket both intact but hanging inside the bumper. My warranty had just lapsed as I surpassed 50k miles, but the service center said the repair wouldn’t be covered anyway. They couldn’t accommodate my same day drive-in understandably. So they scheduled me for 3/10.
Well, being the impatient person I am and not wanting to drive my family around with the parking sensors and assists disabled, I searched online for previous repair resources and guides.
I couldn’t really find on the parking sensor fix however there are a few good YouTube video detailing the frunk and bumper removal.
Long story short, you don’t need to remove the front bumper to replace/reseat the right front (closer to the license plate) by removing the frunk and then reaching in a triangular opening to reach the sensor.
It’s actually easier to remove the sensor from the harness and then repair the bracket with strong double-sided adhesive or a permanent epoxy glue. Once the bracket and sensor are snuggly put back, plugging in the harness is a simple click. Granted, you’ll be doing some of the work without being able to visually see what you are doing, but the process is simple and only takes all of 30 minutes to repair.

I probably saved at least $175 labor charge and possibly some other bogus up sell for a new sensor, so I am pretty happy that I was able to do it within a very short amount of time, and with a 10mm socket wrench and some really strong double sided tape. If I see it coming off, I will use the epoxy glue next time. Since my warranty is done, it seemed like a simple fix for anyone to do

Can you explain a bit more about what you did to access the sensor that was pushed into the bumper?

 

[Hkbruin]

Sorry I don’t check this forum often anymore so I didn’t see your question. To access that front sensor, I removed the frunk and was able to slither my arm in a gap between the hood latch and front bumper assembly. The sensor that was pushed in is connected to a harness so you generally won’t lose track of it as you can feel your way around and find the dangling sensor. Keep in mind this is all done without you being able to see, you’re really only going to be able to see into the little hole in your bumper from the front.
When the sensor gets knocked off, the plastic weld is generally where it comes off. To prep the surface for any gluing or in my case, using 2-part epoxy, I made sure to wipe down around the inside from the front sensor hole with my finger and cloth. Now comes the tricky part. With the right arm that’s down in between the bumper and frame, you have to (sight unseen), unclip the sensor plug and separate from the sensor. The sensor and bracket that breaks off is kind of like a baby pacifier shape. The harness is connected at an angle with a single flat clip on one side, so if you palm the sensor between your hand, you’ll still be able to use your thumb and pointer finger to press the flat clip release and slide out the connector. Of course if you drop the sensor then you’ll have to probably remove the undertray to retrieve it, so be careful not to! After extracting the unplugged sensor, I made sure that the contact surface was flat and sufficient to bond with the epoxy. I tested out the mixture on some other items to get an idea how long it would take to set. Once I had the epoxy applied to the detached sensor bracket wings, I carefully guided the sensor back through the opening and then pressed then sensor back into place and held it there by hand for about 3 minutes. Afterwards I immediately reattached the sensor harness so that it would tether the sensor to the cable, in case for any reason it were to fall out after letting go of the sensor. But, I had no such issue. Do practice putting in your arm into the opening and be mindful of the orientation of the bracket wings as you can easily lose track of the orientation if you twist the sensor in the hole. The flat pieces won’t be perfectly flush against the contour of the bumper unless it it is horizontally placed. I thought about pressing something up against the back of the sensor to wedge it in place to aid in the pressure against the contact surface for the epoxy to cure, however I couldn’t find anything that I could wedge in there that I didn’t think would be an issue if it fell down onto the undertray, so I left it as is.
Fast-forward to today. I’m at 117k miles and my parking sensor is still intact after dozens of drive thru car washes, etc. I hope this explanation helped and didn’t come too late.

 

[HitUpOlas]

Sensor just got knocked in by a bouncing piece of tire tread on the interstate. Thanks for the detailed instructions. Got my tube off JB weld plastic 5min cure tube and I’ll do this tomorrow.