Citroen C5 reversing radar

[tapkaJohnD]

2011 C5 Tourer. When I engage reverse, the car tells me there is a fault with the reversing radar, and it doesn't work.
BUT, the car shows nothing when I press the button to show faults.
AND, my OBD II reader shows no fault.
I have had the reader plugged in as I engage reverse and see the warning, but still no fault.

I bought a PDF copy of the C5 'workshop manual' but that is useless! 0ver 3500 pages, the search facility cant even find "reverse" and searching for the radar system, whatever it is called, by eye found nothuing and left me bog-eyed!

Any ideas on where to look for the problem?
Can't be just one sensor, as there are several across the rear - a fuse or the central control box? Where they?

Thanks,
John

[Scrump]

A standard OBDII reader will pick up engine and emission related faults, often a car manufacturer specific code reader is needed to pick up other fault codes (such as parking systems).

It could be as simple as a single faulty sensor, I had this on a relatives car a few years ago.

[Emanresu]

Get yourself a stethoscope. Put the car in reverse, engine off obviously, and put the stethoscope to the reversing sensors one by one. If a sensor is good you will hear ticking, if it’s bad you won’t hear anything. If all the sensors are quiet, you need to look at the wiring and control unit.

[Boosted LS1]

It wants to do the decent thing.

[tapkaJohnD]

Thanks, all (except boosted)

They tick?? Who would have thought that?

John

[drdino]

You need Citroen's diagnostic equipment to diagnose the park aid ECU.

Have a listen to each sensor in a quiet environment, you should be able to hear them tick.

[tapkaJohnD]

Thanks for the tick check advice!
Problem is - the car will not engage reverse unless the engine is running. So foot needed on clutch, while listening at the rear!
Need to wait until I cam have an assistant, which won't be for at least 12 weeks.
The dealers have closed for the duration and I can't claim to be an 'essential user', so jjust have to wait.

Ho HUm
John

[tapkaJohnD]

They do indeed tick, and I IDed the one that didn't, ordered a new sensor online and fitted it - easy peasy.
BUT, it still don't work. I surrendered and took it to an independant, who chortled softly and told me that Citroen uses EXACTLY the same sensor as I had fitted, except it's tagged. The system will accept nothing but a Citroen-tagged sensor.

So, in all honour, I had him order one and fit it, twenty times the cost of DiY, but at least it works now! Thanks again for the 'tick' tip!

JOhn