16955 brake switch fault (but probably not brake switch)

Fatfranky

Member
Hi guys

I don't know if anyone can offer any help, but my girlfriends A2 has a fault, the EML was coming on (flashing) intermittently !I scanned it with VCDS and came up with the above code.

From a quick google it would appear that the brake light switch was faulty, I picked up a switch at Euro parts the other day the switch he gave me was not the same (blue rather than black!) but did not sort the problem. I dismantled and cleaned the dirty contacts in my existing switch, did not sort problem either.

I then swapped the switch from my 2002 vw T4 van which was the same part number (no fault lights) and the warning light on the A2 still stays on!

Although I have clearly not tried a new genuine switch all of the above suggests that the switch is not the problem! I don't know if this is relevant but before I interfered the problem was intermittent but now it seems almost permanent. VCDS will not clear the code even for a minute

Can anyone suggest where I should look/ check next??

Many thanks

Frank
 
Similar issue a while back, i changed brake bulbs (correct wattage), i had a flashing coil light error rather than a eml, also found a blown fuse, sorry can't remember which one but worth a check.
 
Last edited:
Similar issue a while back, i changed brake bulbs (correct wattage), i had a flashing coil light error rather than a eml, also found a blown fuse, sorry can't remember which one but worth a check.
Yes, it could be that both bulbs have blown, that gives exactly the same error.
If the bulbs are fine then try the fuse.

It is worth remembering that when you change the switch you sometimes have to reset the length.
The plunger on the switch can be pulled further out, once it is fitted it automatically pushes in to the correct length.

Steve B
 
Last edited:
Thanks for the advice guys, since posting this last night the warning light has now gone off of its own accord, but I would still appreciate any advice in case it comes back again.

I'll try and explain more clearly:-

When we bought the car back in February there were no warning lights during the test drive, but a couple of days later the glow plug warning light started flashing whilst driving, stopping the car tended to reset it but generally speaking it would re-occur. Then other days it would be fine, no warning lights, when the fault did happen I checked the brake lights and they were a bit intermittent, sometimes working sometimes not!

I scanned with VCDS and came up with the above code, a bit of googling suggested that faulty brake light switches were not uncommon so I hoped this would cure the problem, the car was then SORNED till April, and last weekend I called at Euro Car Parts, they said that there were 2 different switches and that I could buy both and return the incorrect one, one of them was purple, the other green, my original was black and a different shape.

If I fitted the purple one, the brake lights were permanently illuminated, if I fitted the green one (or later my original with clean contacts or the T4 one) the brake lights worked fine, but the fault light came back on within a few minutes, even if I did not fit the switch to the bracket but just left it hanging. When I tried clearing the fault VCDS would clear it momentarily but it would immediately recurr despite not touching the pedal or the switch.

I hope this makes things clearer, as I say the light is currently off, but I'm unsure whether it is going to come back

Best regards

Frank
 
Thanks for the advice guys, since posting this last night the warning light has now gone off of its own accord, but I would still appreciate any advice in case it comes back again.

I'll try and explain more clearly:-

When we bought the car back in February there were no warning lights during the test drive, but a couple of days later the glow plug warning light started flashing whilst driving, stopping the car tended to reset it but generally speaking it would re-occur. Then other days it would be fine, no warning lights, when the fault did happen I checked the brake lights and they were a bit intermittent, sometimes working sometimes not!

I scanned with VCDS and came up with the above code, a bit of googling suggested that faulty brake light switches were not uncommon so I hoped this would cure the problem, the car was then SORNED till April, and last weekend I called at Euro Car Parts, they said that there were 2 different switches and that I could buy both and return the incorrect one, one of them was purple, the other green, my original was black and a different shape.

If I fitted the purple one, the brake lights were permanently illuminated, if I fitted the green one (or later my original with clean contacts or the T4 one) the brake lights worked fine, but the fault light came back on within a few minutes, even if I did not fit the switch to the bracket but just left it hanging. When I tried clearing the fault VCDS would clear it momentarily but it would immediately recurr despite not touching the pedal or the switch.

I hope this makes things clearer, as I say the light is currently off, but I'm unsure whether it is going to come back

Best regards

Frank

If you have tried various switches ad the problem still happens, then check the bulb holders and ensure that the bulbs are properly seated and the wiring connectors are fully engaged.

Whatever is causing it, the brake lights are not functioning correctly, whether it is the switch, the wiring or the bulbs.

Steve B
 
Thanks for all the help guys.

Just to update problem seems to be resolved, but I thought I should update the thread in case anyone searches this fault in future.

Basically, the fault would not clear with either the Euro parts switch nor the original which I stripped, cleaned the contacts and re-assembled (though in both cases the brake lights worked fine, but the fault light came on)

When I fit the switch that I robbed from my T4 brake lights work and fault light stays off!!

Morale of the story, genuine switches seem to be best.

Hope this helps someone in future.

Best regards

Frank
 
Just spent 3 days trying to fix a faulty brake switch, (fault 16955 P0571) and flashing glow plug lamp on dash. Got new switch (not OE) didn't work ! Checked fuse, switch plug, bulbs and bulb sockets. tearing hair out now, driving without brake lights not recommended! Read members post regarding taking the original switch apart, and, sure enough the contacts inside were dirty. Sanded/cleaned all the contacts, put it back together and into the car, three attempts to get the switch plunger at the right length, and, let there be (brake) light. Swiftly returned new switch to shop for money back. As Fatfranky says morale of this story, do not buy non OE electric bits, but, more importantly take the switch apart for inspection /cleaning first.

Saltire
 
Ok so decided to invest in new brake switch - not OEM - but it has the 4 poles etc and on visible inspection it looks identical.

Its this one here:

http://www.ebay.co.uk/itm/BRAKE-LIGHT-PEDAL-SWITCH-FOR-AUDI-A2-A3-1J0945511A-NEW/401345717575?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20131017132637%26meid%3D80a1f9ca1d954defaa1bacc815b25670%26pid%3D100033%26rk%3D1%26rkt%3D8%26sd%3D401345717575

So been trying for almost an hour now to get it to go in and turn but cant seem to get the lugs in the holes evenly so they can turn to the right and lock.

Is there a knack to it? I seemed to get the OEM one back in okay before.

Oh and when I first put the new switch in it wasn't properly seated but wired up - which then caused my sidelights to come on? Is this normal?!
 
Ok so decided to invest in new brake switch - not OEM - but it has the 4 poles etc and on visible inspection it looks identical.

Its this one here:

http://www.ebay.co.uk/itm/BRAKE-LIG...5b25670&pid=100033&rk=1&rkt=8&sd=401345717575

So been trying for almost an hour now to get it to go in and turn but cant seem to get the lugs in the holes evenly so they can turn to the right and lock.

Is there a knack to it? I seemed to get the OEM one back in okay before.

Oh and when I first put the new switch in it wasn't properly seated but wired up - which then caused my sidelights to come on? Is this normal?!

If your brake light switch is causing your sidelights to come on then I would recommend checking again that your "stop and tail" bulbs are correctly seated. It is very easy for them to appear to be in correctly but it is the only likely cause of that strange issue.

There is no knack to getting the brake switch in other than making sure you have the pedal pressed down when you are doing it.

The new one will probably have the actuator rod sticks out further on new ones until they have self adjusted.

Steve B
 
If your brake light switch is causing your sidelights to come on then I would recommend checking again that your "stop and tail" bulbs are correctly seated. It is very easy for them to appear to be in correctly but it is the only likely cause of that strange issue.

There is no knack to getting the brake switch in other than making sure you have the pedal pressed down when you are doing it.

The new one will probably have the actuator rod sticks out further on new ones until they have self adjusted.

Steve B

Couldnt get it to fit so put the old one back in - and this time remembered to press the brake pedal :eek:

So it may not come back this time - certainly the flashing symbol now off but it did have a habit of going off then maybe 40 miles later it would be back!

Anyhow what is curious is that the lights are now coming on when i Press in the brake pedal. I've fitted the auto sensing switch - so disconnected it and the problem went away.

Is it the switch??
 
Couldnt get it to fit so put the old one back in - and this time remembered to press the brake pedal :eek:

So it may not come back this time - certainly the flashing symbol now off but it did have a habit of going off then maybe 40 miles later it would be back!

Anyhow what is curious is that the lights are now coming on when i Press in the brake pedal. I've fitted the auto sensing switch - so disconnected it and the problem went away.

Is it the switch??

Robin also seems to have a situation where the side lights come on with the ignition, but not related to the brake lights or the brake pedal.

Is this happening to you too?

Steve B
 
No just when I depress the brake.

It was working fine until I went in to change the brake light switch if I'm honest so something has happened but I'll be damned if I can find a way to trace this one.

I'll put the old switch back in to see what that does also...
 
No just when I depress the brake.

It was working fine until I went in to change the brake light switch if I'm honest so something has happened but I'll be damned if I can find a way to trace this one.

I'll put the old switch back in to see what that does also...


It sounds like a poor earth or faulty connection (that is if you are sure the bulbs are installed correctly)

I would check the rear light cluster connections and loom.

Steve B
 
Ok correction...flashing symbol back on so went and got another brake light from scrap merchant. Initially worked then flashing came back.

What's funny here us that when I press the brake pedal When the car is turned off I'm getting the light buzzer coming on...which may explain why the auto dim switch is turning lights on when I brake!

As you've said Steve I think now I'm edging towards some kind of loom wiring or grounding issue. Suspect I'll be asking timmus to gave a look next week when I'm down.

Ah the joys of buying a 13 year old car :)
 
Ok correction...flashing symbol back on so went and got another brake light from scrap merchant. Initially worked then flashing came back.

What's funny here us that when I press the brake pedal When the car is turned off I'm getting the light buzzer coming on...which may explain why the auto dim switch is turning lights on when I brake!

As you've said Steve I think now I'm edging towards some kind of loom wiring or grounding issue. Suspect I'll be asking timmus to gave a look next week when I'm down.

Ah the joys of buying a 13 year old car :)


I have seen this exact problem before and it was the stop/tail bulb incorrectly fitted and the contacts were touching the side light contact instead of the brake light contact.

Have you checked both bulbs, as suggested, it only takes one of them to be in wrong to cause the issue.

Steve B
 
I had but will give it another go Steve especially as you've seen it before . I have a spare rear light cluster holder if needs be that I can try.
 
Last edited:
Yup so brake bulb wasn't seated quite right!

All that hassle with brake light switches and they were not the issue..now got an issue with the socket for fog lamp will need to maybe clean the connectors up and retry.

Massive thanks for steer Steve .
 
I’ve been having very similar problem. For some time the blown brake light bulb and alarm would come on, even though all brake lights were working.
For the last couple of weeks EML has been on constantly. About a week ago I had the flashing glow plugs light whilst driving.
Borrowed a mates cheap scanner it displayed 16955 (along with 17055,56&57)
I’ve replaced the brake light switch and both bulbs, I’ve cleaned the holders and even swapped holders with some spares. I’ve even removed the non-OEM auto headlight switch, all to no avail, though the EML is no longer on, but flashing glow plugs light remains.
Any ideas?
 
Back
Top