[EOS_CH]

Hi
Since a few days there is a strange noise, sizzling at the front right, just behind the cooling liquid reservoir, under the right hinge of the hood, coming out of the car, somewhere inside the car.

It is always there even when engine is not turning and car keys are out of the car. It only stops when I unplug the battery and even then it takes 20-60seconds to disappear.

It can be heard the inside of the car when you put your ear under the glove compartiment or from the outside just at the hinge of the hood.

Similar to a shortcutting, sparkling wire, or condensor, I do not know. Please listen to the noise under the following link. noise

Thanks for the help.

 

[voxmagna]

Sorry I couldn't make much of the recording but I appreciate your concen. You could try a couple of things. If you have an old A.M portable radio, put it on the medium wave band and search around, that may help located an arcing wire.

Have you got any rodents in there munching on Swiss cheese?

Your car is left hand drive and I can't get my head around where things are compared to my right hand drive. Are you sure it's not coming from the battery (an internal short?). You can open up the engine bay fuse box and check all the fuses and socket contacts are clean.

Have a diagnostics scan done.

Look around the engine bay in the dark.

 

[EOS_CH]

noise

Hi
thanks for the reply. I have tried the AM radio. Nothing special.
I'll check it tonight for any light.

For your info, here a photo.

Kind regards

 

[David44]

Air leak from expansion tank???

 

[voxmagna]

O.K I'm going for a shot in the dark. First I would have scanned the car because I'm fortunate to have VCDS. The reason being a steering controller module is somewhere in that area and also the wiper motor. Finding a trouble code which has not put up an engine fail would be a strong clue.

But my pitch would be for the wiper motor. When you disconnect the ignition, the wiper motor is still powered to allow the wiper arms to stop at their park position. That might explain why you hear noises when the key is out. Try operating the wipers a few times, remove the key and see if the noise is still there or put them into the 'service position' - key in, then out, push wiper button down once. That should put the motor cam clear of the park switch.

My suspicion is that the motor park switch contacts integral to the wiper motor may be arcing, because the contacts are dirty or are not being fully opened. Make sure the wiper blades still have some travel left at the bottom of the sweep so they can park - i.e stop at the correct place and open the parking contacts. Put some gentle downwards pressure on the wiper blades and see if the noise goes away. Lift the wiper arms off the glass, operate the wipers and see if the same noise is still there if audible above the normal wiper motor noise.

It is difficult to see fast current changes with a digital multimeter, but you could try connecting a current meter in series with the battery lead. With the doors closed and courtesy lights out, there will be a residual small current from the CAN electronics, which should drop to a very low current after 4 or 5 minutes. Current draw above a few milliamps and fluctuating could indicate a problem, and of course battery drain if leaving the car several days. Do NOT try starting the car or open the doors whilst doing low current drain testing!

 

[EOS_CH]

Thanks for the replies. I did some of the checks suggested by Voxmagna.

Current: putting a amp meter between in series gives a huge current of 1.6 to 1.8 Amp. So I am glad I disconnected the battery theses last days between use.

It sound like arcing.

Wiper test. I started what you were saying but once lifted in parc mode. If I operate the wipers they will smash into the hood... isn't it. Or do you mean something else.

One more thing. When I disconnect the battery, the noise is still audible for a while.

Anyway, looking this current of more than 1A, I took an appointment with the garage and I will let you know what it was.

Thanks a lot.

 

[voxmagna]

but once lifted in parc mode. If I operate the wipers they will smash into the hood

I didn't expect you to operate them or pull the arms back. Just listen with them parked in a position which is not their normal stop position when the key is out.

Did you check the current drain after several minutes, because it takes a while for the cabin lights and CAN to shut down. If you are still seeing 2 amps, then you still have a problem. Let's say about 75Ah for the battery then in a day and a half it will be flat!

Post back what they find.

 

[EOS_CH]

Hello
So 300CHF later , it seems the siren (see picture) was dead and arcing.

Now we know what is in there

Kind regards and thanks to all.

 

[voxmagna]

Better to have found it now than had a fire or problems with flat batteries. I guess the alarm circuit is something else active when the key is out.

Test the alarm now to check it functions o.k. Also still worth checking the current draw to see if it has gone right down.

 

[EOS_CH]

Hi
Just came back to the forum.
Testing the old alarm or the new one. Anyway, I would not know how to test the new one or even the old one?

I tested the drain and there is no significant current going out.

One question VOXMAGNA, the VCDS you mentioned is used with an ELM327 connector, correct? The ones found on ebay for exemple?

Thanks a lot

 

[voxmagna]

Current drain insignificant, so now all good.

ELM327 based diagnostics is a general purpose tool working with most cars that will give you high level fault readouts as codes, but then you will have to search for what those codes mean. Manufacturers have to now provide the basic information required to allow 3rd parties to produce diagnostics tools. But note they only provide what they have to. They are not required to give information that would allow you to change things!

A workshop diagnostics tool not only reads back data from the ECU and controllers, but should interpret it and give some help as to what is going on. It is no good getting back a string of hex code then have to find out what it means. The tricky part comes when you have to do 'adaptation'. That is, WRITE code back to the car to alter or change functions or in some cases replace a car module and recode it same as before. I would not trust anything which is not VAG specific to do that. Just like you can brick a component in a PC doing a firmware upgrade or change, the same is true writing back to your car controllers. You don't want the embarassment of having your car towed to the dealer because your coding got screwed up.

Therefore the tool needs to interpret the data it gets back and put that into simple english. VCDS comes with a long coding helper utility which does that. More advanced tools like VCDS can monitor car functions in real time so you can see and log to hard drive what is going on when the engine is running. You can even make changes, operate the accelerator etc from the laptop screen.

You need to be careful with ELM 327. It is based on a Microchip PIC but all the Ebay versions you see are level 1 firmware. I actually have a genuine ELM327 chip to play with which has more advanced firmware. But ELM327 is only the diagnostics controller hardware. It still needs a software interface GUI. Whilst there is some basic free software that is usually bundled with the tool, more advanced software usually has to be paid for.

VCDS works well because of the feedback and support from VAG owners which makes it a tool close to what VW might use. When you have an EOS you may want the diagnostics tool to help with the convertible top. There are 12 or 13 sensors and a pump involved. I doubt if ELM327 based tools will come with an EOS specific data interpreter to read and translate roof error codes for you.

 

[EOS_CH]

thanks a lot for your detailed response.
You made me want to try one of these...and I'll follow your advice
Regards