Author Topic: Problem with reverse sensors  (Read 3092 times)

dnloreto

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Problem with reverse sensors
« on: November 01, 2020, 08:17:27 PM »
Dear Jazz'ers,

The car was bought from the dealer with the reverse parking sensors as an extra. It worked well for many years. A couple of weeks ago it no longer works properly. As soon as I engage reverse, the regular "pi" is emitted to let me know I engaged R (and not 4th) and then a deeper "piii" keeps on constantly, even with nothing behind the car. Check the youtube video if that helps:
So far I tried the following:
1) Cleaned the sensors. No change;
2) WD40 on the sensors in case it was humidity inside (I used to have car on underground parking but I moved in August and now the car sleeps on the side of the road). No change;
3) Checked all fuses under steering whell that had no specific function associated in the diagram (as this is an extra) but all fuses were OK;
4) Recorded video of the sensors with car idling and reverse engaged and could hear on the video all 4 sensors doing the "clack clack clack" as proof they work. Another video: 5) Used an ODB2 wifi dongle and torque on my android to check ECU errors but nothing there (maybe because the system has an ECU of its own?);
6) Inside the boot, took the cover for the rear lights on the side oposite to the fuel filler and there was the reverse sensor ECU. It's a Bosch ParkPilot 0263004011. Seems to have been fit by dealers on many Honda, Open, Audi, etc. See photos attached, still haven't figured out how to embed. Disconnecting it took away ALL noises (of course).

Now... Research on the web states that maybe there is a fuse on the wiring there but I saw none and before I disassemble the cover for the whole boot, I would need to know if it is worth it...
A specific web result was of a guy saying the noise was fixed by replacing the buzzer. I find that odd but I don't know if the problem was exactly like mine. I still haven't identified the buzzer's location either as I have some hearing restrictions that make it harder to pinpoint from where the noise comes.
Another web result for a similar Bosch ECU said there was a way to run diagnostics but it was a unit with leds and I don't know how to do that on this one.
I checked the web and from breakers I can get a ECU like this for around 50€ (new only found one for 400£ ahahah no way!).

Soooooo..... Please help me with your opinions or past experience!
Find the buzzer and replace it? Disassemble cover of boot and look for a fuse on the wiring and check it? Replace the ECU? Open the ECU and check for a specific component that may have failed (I can handle some degree of solder and electronic components and own a multimeter)? Is there a way to run ECU diagnostics that I should try first?

Thank you very much for your patience reading through all this!
Duarte
« Last Edit: November 01, 2020, 08:21:07 PM by dnloreto »

dnloreto

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Re: Problem with reverse sensors
« Reply #1 on: November 02, 2020, 09:37:53 AM »
An update as I make questions but can't avoid keeping on it.
Looked for the fuses and they were reachable from the whole on the boot cover.
It has two "fuses". One is a 2A fuse, the other a 110ohm resistance.
Used the multimeter and tested the fuse for continuity, it worked. Then tested the resistance on the other one and it gave the 110 spot on. So, it's not that...

sparky Paul

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Re: Problem with reverse sensors
« Reply #2 on: November 02, 2020, 11:03:58 AM »
In the absence of any other replies, the only thing I can say about these systems is that most of the problems are down to faulty sensors.

I think the Bosch system is one of the more reliable systems, they do usually keep working, unlike some of the aftermarket efforts. Lack of replies is probably down to this and the fact that not many had them dealer fitted.

dnloreto

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Re: Problem with reverse sensors
« Reply #3 on: November 02, 2020, 03:04:48 PM »
Thank you for sharing with me, sparky Paul!

Well... From what I read before, if a sensor was faulty, recording a video with the phone next to it wouldn't allow listening to a "clack clack" noise. Other way to test is to lightly put the index finger on the sensors and if we feel a tingle, they are working. But it could be wiring to the ECU...

Anyway, I found how to diagnose. Take the resistance I found on the wiring off, turn on the car and shift into reverse and the beeps are a diagnostic. Problem is I don't have the manual to interpret the diagnostics... I mailed Bosch asking for it and went to the car just to see what beeps would come out of it. So, as soon as I got a reply, I would be able to read without going to the car.

And, all of a sudden, it works again! I read that taking the resistance off is also the reset for the ECU. And that just made it work for me.

In the mean time, looked for the buzzer and is under the plastic that covers the parking brake lever and the shifter, on the passenger's side. Didn't take the cover off to look at it since now it was working.

I wonder why it failed all of a sudden. But I'm happy it now works. I'll come by to update the thread if Bosch comes back at me with the manual!

Thank you all for reading and thinking about this and specially to sparky Paul for participating!

sparky Paul

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Re: Problem with reverse sensors
« Reply #4 on: November 02, 2020, 04:13:25 PM »
I guess it's possible that an intermittent fault, perhaps with a sensor, caused the control unit to lock up. At least it's working now, hopefully that's sorted it out - at least you appear to have worked out how to reset it if it happens again.

I'm sure all the usual contributors will have read your post, but like me, probably didn't have much useful to add. I don't like anyone to think that they are being ignored though  ;)

Anyway, hope it keeps working - and your experiences might prove useful to anyone having similar problems in future. You are now the resident expert on these systems!  ;D

dnloreto

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Re: Problem with reverse sensors
« Reply #5 on: November 02, 2020, 05:58:20 PM »
Thanks again, sparky Paul, for your concern and kindness! As for me becoming the in-house expert on Parking Aids, it is just like my job! Touch something no one touched before and it doesn't explode, you become the "in house expert". LOL  ;D

Went to pick the kids from school, used the older kid to test. The reverse beeps start closer to the car, as if I lost some range. The manual for a different sensor said that when resetting the system I should have no obstacles near the sensors. Actually I didn't take care, the car was near the house's wall. So... Maybe I'll have to reset it soon when I get time near an open area.

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