ASR & ABS & Red ( ! ) - but no EML fault code

Sylvester

Active Member
Hi guys, my A2 had been off-road for almost 2 months, sorting out engine-related issues, MAP sensor & Throttle Body, topics found in my profile.

5 days no issues, but today after an hour drive, the asr, abs, and red flashing (!) came on at once a minute away from home, with vibrating brake pedal and some knocking sound. No engine light. Warning lights disappear when restarting the car, but issue starts over.
Driving again an hour later, the symptoms turned worse, every 10-15seconds the brake pedal vibrating on its own violently along the warning lights, slowing down helps only for a few seconds but beep/juttering re-appears again, feels like the whole brake system is about to fall apart or the car keep hitting a stone of wall. More stress I don't need at all.

I've checked the brake-guard for possible stuck stone chips, but nothing.
ABS sensor wire been disconnected before I bought the car, just hanging there.
Only thing I've noticed, that after being offroad, the rusty brake discs don't clean up evenly.
Any idea what it can be? Thanks
 

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Catnip64

Member
ABS sensor wire been disconnected before I bought the car, just hanging there.
If this is the ABS sensor wire and not the brake wear sensor then this won't help at all as the system will not be receiving data from that corner of the car and will flag up an error. Probably best to scan the car (VCDS) to see what it's indicating, reconnect the sensor and then retest.
 
D

Deleted member 16918

Guest
The disconnected ABS wire will certainly have given you the warning lights you are getting, I had this problem myself. The vibrations could be a warped disc.
 

kp 115

Member
Hi guys, my A2 had been off-road for almost 2 months, sorting out engine-related issues, MAP sensor & Throttle Body, topics found in my profile.

5 days no issues, but today after an hour drive, the asr, abs, and red flashing (!) came on at once a minute away from home, with vibrating brake pedal and some knocking sound. No engine light. Warning lights disappear when restarting the car, but issue starts over.
Driving again an hour later, the symptoms turned worse, every 10-15seconds the brake pedal vibrating on its own violently along the warning lights, slowing down helps only for a few seconds but beep/juttering re-appears again, feels like the whole brake system is about to fall apart or the car keep hitting a stone of wall. More stress I don't need at all.

I've checked the brake-guard for possible stuck stone chips, but nothing.
ABS sensor wire been disconnected before I bought the car, just hanging there.
Only thing I've noticed, that after being offroad, the rusty brake discs don't clean up evenly.
Any idea what it can be? Thanks
Hi Sylvester,
Have you checked the condition of the brake pads as a low pad or failed friction pad could also cause this effect.
Keith.
 

Sylvester

Active Member
The disconnected ABS wire will certainly have given you the warning lights you are getting, I had this problem myself. The vibrations could be a warped disc.
Abs wire been disconnected for years, no issues until recently. The wrapped disc might be something to check as the car was off-road for nearly 2 month, but the problem appeared after 5 days issue-free driving, perhaps the wrapped discs would've showed signs right away?
 

Sylvester

Active Member
Hi Sylvester,
Have you checked the condition of the brake pads as a low pad or failed friction pad could also cause this effect.
Keith.
Brake pads are on good condition, only thing is, as the car was off-road for 2 months the discs had surface rust, but after 5 days driving still some rust show in circles, so the pad doesn't clean evenly.
 

Sylvester

Active Member
If this is the ABS sensor wire and not the brake wear sensor then this won't help at all as the system will not be receiving data from that corner of the car and will flag up an error. Probably best to scan the car (VCDS) to see what it's indicating, reconnect the sensor and then retest.
Yes that's true, I'm not exactly sure that disconnected wire is ABS related, as the ABS been working fine. Might be the pad wear sensor, I'll take a picture of it tomorrow.
 

Edwrai

Member
Yes that's true, I'm not exactly sure that disconnected wire is ABS related, as the ABS been working fine. Might be the pad wear sensor, I'll take a picture of it tomorrow.

Pad wear sensor won’t cause this. Check your brake fluid level.


Sent from my iPhone using Tapatalk
 

Proghound

Admin Team
Brake light switch? Caused all the alarms/lights to come on in mine. If your ABS is sensors are also disconnected, maybe it could get more stroppy and try braking as well?
 
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Deleted member 16918

Guest
I have disconnected my brake wear sensor. It is on the front passenger side wheel. This may be what has been disconnected on your car, rather than the abs.
The warnings you are now getting, I also had, were in my case ,for a faulty ABS sensor.
 

Sylvester

Active Member
I have disconnected my brake wear sensor. It is on the front passenger side wheel. This may be what has been disconnected on your car, rather than the abs.
The warnings you are now getting, I also had, were in my case ,for a faulty ABS sensor.
That probably what it is, makes much more sense. Was that issue intermitten?
Like no symptoms for days, then issue appears a lot for 1-2 days, then following days nothing again? Thanks
 

audifan

A2OC Donor
You need a full VCDS scan to prevent pure guesswork. Chance that you have a corroded plug that is intermittent. Come back with the scan results.
 
D

Deleted member 16918

Guest
That probably what it is, makes much more sense. Was that issue intermitten?
Like no symptoms for days, then issue appears a lot for 1-2 days, then following days nothing again? Thanks
My issue was constant. It may be the shaking that is causing the fault in your case. The disc is more likely to be badly seated than warped. It costs nothing to clean up where it seats on to the hub and also make sure that the wheel is on evenly as it is the wheel bolts that keep the disc secure.
You can get a basic diagnostic reader for under £10 which should tell you which wheel sensor is problematic.
There is free software that requires a laptop.
 
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