Overactive parking sensors

[jml]

Thanks Marc.

Is it worth me testing the other terminals etc ? Do you have access to a wiring diagram for the parking assistance system ?

Cheers

Julian

[jml]

Hi Marc,

Sorry if I’m being a pain with this but in my attempt to sort my problem out I’ve just come across something that seems slightly odd and I was hoping that you might have access to a wiring diagram that could clarify things.

I’ve just checked the parking sensor cut out switch that is on the dash. It is a Valeo switch with four terminals. On checking I don’t find any continuity between any of the four terminals in either of the two on/off switch positions. That doesn’t sound quite right to me. Would you be able to see how that switch should operate (although I can’t see any terminal numbers marked on it) ?

Also would you mind kindly giving me the part number and price ? Thanks in advance and, again, sorry if I’m a nuisance !

Cheers

Julian

[GiveMeABreak]

No problems Julian - give me a few minutes....
Here's the Main Diagram

7500 is your PA ECU
7515 is the PA Cut off Switch




Cut Off Switch
A bit more detail of the cut off switch:

[jml]

Many thanks Marc,

Well that confirms my thoughts that the cut off switch shouldn’t be open circuit on all terminals ! My investigation will continue but, in the meantime, would you mind giving me the part number of the switch.

Cheers

Julian

[GiveMeABreak]

Yes, it's part: 6490EG and costs £32.35 from Citroen, but make take a while to order up.

[jml]

Thanks again Marc

[jml]

Hi again Marc,

I’m still trying to get these sensors sorted, unfortunately my efforts have been delayed by serious illness recently.

The problem is fairly erratic, sometimes they work ok for a few days, other time the front warning lights up and blares out as soon as I select 1st gear. Because of lack of time I’ve reluctantly gone down the lazy route of obtaining a replacement, correct, ECU, and on/off switch, but they make little or no difference.

I suspect dampness in the wiring somewhere, as I think you once suggested, but I still don’t know how best to check the very thin wires for continuity or resistance - how do people get a reading from these ?

My other question is, is there a way to just check the individual sensors ? Resistance ? Continuity ? Etc.

Hoping you can help,

Cheers

Julian

[GiveMeABreak]

Hi Julian

Very sorry to hear about your health.

With Diagbox connected, you should be able to check which parts are reporting a problem. Either by interrogating the ECU or checking the live data, as you engage forward and reverse gears, which should help identify the particular sensor connection (s) that are coming up the most as faulty. As I think I mentioned, when there is a communication problem with one or more sensors the whole system packs up.

If this is intermittent it should help identify which one of the sensors it is happening more frequently to than the others as a starting point for investigation.

Another way is to have the ignition on and put the vehicle in reverse or forward gear and use your finger to check the pulsing sensation you should feel as you hover a finger over each sensor. The one without a pulse when the system is operating is usually a good indicator of the problem sensor or wire.

[jml]

Thanks Marc,

I’m still very much a novice with the Diagbox and I’m learning my way round it slowly ( there isn’t an idiot’s guide anywhere is there ?). So I’ll try to find out how to check live data.

I remember doing something like that once and I think it just said ‘check the operation’. I went in front of every sensor but didn’t draw any conclusions then but, as soon as I can, I’ll have another go.

Your ‘pulsing sensation’ is very useful and I’ll give that a try.

Thanks again and I’ll try to give some feedback when I find out more.

Cheers

Julian

[GiveMeABreak]

No problems, let us know how you get on. Can you confirm whether Diagbox itself launches (newer interface), or does it then launch the Lexia interface Julian?

[jml]

Hi Marc,

I get a screen that shows boxes for both Lexia and Diagbox - I’ve always clicked on Diagbox, which, I hope, is the right thing to do ?

Cheers

Julian

[GiveMeABreak]

Yes, that's the better interface Julian. Easier to navigate too.

Undertake a Global diagnostic, then after that finishes, look for the parking assistance ECU in the list (should be called AAS). Select AAS and confirm, then you should be taken into another menu where the parameter tests are an option. You can select what sort of test you want and see what is offered.

[jml]

That’s great, thanks Marc.

I’ll come back as soon as I get the chance to investigate this

Cheers

Julian

[lifechooser]

Apologies for the thread resurection, but it has so many great images. My parking sensors don't work and I'm suspecting it may be the speaker at fault. When I activate them, I get a single measurement on the screen and then the failure message.

The issue I have is that I can't locate the speaker. Does anyone know where it is located?

[GiveMeABreak]

I doubt if it's the speaker. The system self-checks on engagement and if there is a fault it will disable the system temporarily.

To find the cause you need to have it diagnosed with Lexia and put the fault codes up here. No good swapping parts out unnecessarily as I've never yet known the speaker to be the issue.

It's more likely to be either a faulty sensor, the wiring to it, or the parking assistance ECU.