Parking sensor problem
 

Now, I've had parking sensors go before, and replaced the control box, but this is a bit odd.

When starting from cold, the front sensors beep continually (each beep lasting2 or 3 seconds or more) with short gaps between the longer beeps. Once the car is fully warmed up, they work normally.

There are no VCDS fault codes and the green light on the switch doesn't flash (IIRC, it does when one of the sensors is faulty).

Any ideas?

sounds to me like you may have some condensation (or dirt) occurring between the sensor and the paint layer or getting down the sides of the sensor(s) - so the detection is working but its trying to suggest you're about to hit something!
The only solution i guess would be to replace the sensor in question with a newly sprayed one or try to clean out what's there or take the sensor out and clean / respray it ?

But I don't know which sensor it is! :(

Not a job for before the meet if I have to take them all out - too busy with polishing, leather renovating, headlight lens cleaning and carpet shampooing!

I gave mine a quick wash and polish yesterday, but we've got a week in the rainy/muddy Lake District now, walking etc. so it will look like a refuse tip when I arrive in Wales directly from there! :o

vagcom (or whatever variant you have) will tell you which one it is Jim

Read the first post! :) - there are no fault codes

I think he meant to check measuring blocks with VCDS, it will show the readings from individual sensors, the odd one must be faulty.

OK, I can do a scan with VCDS and I've even managed to recode with it to allow the use of the radio clock.

But I have no idea how to check the measuring blocks!

Have a look here: http://forum.a8parts.co.uk/showthread.php?t=5000

Thanks Ainars, much obliged +++

Just need to call David to get a hold of our shared VCDS.

Since you've got no fault codes, sounds to me like the bleeps are the normal 'obstruction' bleeps and that the system 'thinks' there's an obstruction because a sensor in misbehaving enough to cause a false positive but not enough to trigger a fault code.

My guess would either dirt/moisture, as Neil suggested, a partially failed/failing sensor or damp/dirty connector.

I've had to chop off and replace a couple of my front sensor plugs due to moisture and corrosion. It's possible one of yours may at the early stages of that; not enough to cause an open circuit but enough to interfere with the signal.

I'd take the bumper off and check/clean the connectors. Might be worth buying a spare sensor or two beforehand in case it turns out to be a failing sensor.

A job for after the meet!

I checked the measuring blocks, and they're all exactly the same, so still no clues.

And now the problem has gone away! :)

I'd say almost certainly caused by contact moisture/corrosion in that case. The engine heat from the journey has probably dried the contacts out.

well the sensors on mine are just ornamentation , ie , engage reverse , makes noises , nothing works except the light on the switch flashes

so that means there is a faulty sensor somewhere ? does one u/s fail the whole system ?

no VCDS around here .... maybe when I move to southampton next year there will be some kind soul with one in easy reach !

Yes, that's it exactly. One faulty sensor and the whole system fails. Only a VCDS will tell you, unless you can be bothered to replace one sensor at a time until it's fixed.

If anyone is desperate I have an ancient laptop that I used to run VAG-COM on (for many years), complete with serial OBD-II lead. Free to a good home! +++

It's battery is dead so you have to run a long mains lead out to the car, but apart from that it works fine. IBM ThinkPad of some variety, built like the proverbial brick privy so almost indestructible, running Windows ME.

Has various versions of VAG-COM on the disk. One of these was properly registered and most definitely worked, but I deactivated it to upgrade to VCDS-Lite on a Windows 7 laptop.

Also has VCDS-Lite installed but not tested. If anyone is interested I'll plug it in and check that works OK, I expect it will.
As you presumably know the unregistered version of VCDs is still pretty useful. :cool:

If you can't be bothered with a mains lead you can probably buy a power adapter that will generate the 16V DC it uses and plug into your car 12v power outlet. I have one for my W7 laptop (Dell 19.5v) and it's quite handy, not least because the laptop then runs in mains power mode so doesn't keep trying to dim the screen or shut things down (and yes, I know I could override that).

Maybe I should stick this in the VCDS section?

Now tested, works fine. Looked at the "usual suspects" (no auto-scan as it's unregistered) on my car and found and cleared the usual (largely irrelevant) errors.

One good thing about ME is that it only takes a few seconds to boot. :cool:

And the battery isn't quite dead, it will boot and run for a few minutes.

sounds like a good offer , and would be really handy for me !
expect to be back in the uk before year end so can I take you up on that ?
being a motorhomer I have the 12v power supplies so would certainly have no problems in that direction

had a look on the map for HS2 , doesn't seem to be shown ! where are you ? my daughter is often around denham , does it go in that direction , seem to remember some connection with birmingham !

Denham is fairly close to me (less than 10 miles away and I drove by it earlier this afternoon).

I'd like to be shot of it fairly soon so can your daughter pick it up sometime?
(Also advertised on another forum but the responses are less, how can I put it, "inviting". :rolleyes: )

thanks to andrew's kindness I am going to be able to find my faulty sensor and sort out the problem !
in anticipation I sourced a new one from germany , arrived today , correct part number , correct connector , but it ain't right !

the actual sensor bit in the centre isn't the same shape ! it's circular instead of squared off circular ! anyway I gave it a fine emery paper , sprayed the correct colour , finished with lacquer , dried in the hot sun ...looks a treat so will fit !

Ian would have a fit !

There's a thread I've posted in that gives the correct part number and a source in Germany for pre-painted sensors to match your paint code. I bought a set of 4 for the back of mine for about £120 delivered. They sell individually too....

I suppose as I paid £12 delivered in primer I can't complain ....I had the paint /lacquer anyway ; and as I said , they had the correct part number