ABS Alarm

smilesbernard said:
Thanks Andy that's a great help
So likely jack up and search under the car ? Or do you know if this is internal and needs interior stripping out to access?
Thanks again
Click to expand...
Just read on and sounds like

"the earth point from the battery ......It’s behind the carpet just inside the rear left hand door. The plastic door trim is really tricky to put back, but I recon you could successfully just pull the corner of the carpet out.


I'll have a look there

Thanks again
 
Is there still no DTCs, either on the Engine Controller, or the ABS Controller?
You need to scan each one, to check.

The problem we have, is that previously, when the supply voltage was very unstable, and dropped close to 11 Volts, it was quite possible that the ABS Alarms, (were they flashing amber, or red?), were simply a symptom of the unstable voltage, and not related to an the ABS Controller.
If the voltage is as stable now, as it was in the last log, then the ABS Alarms are likely genuine.
If there are no ABS DTCs, then they maybe Warnings, caused by a transitory condition, that triggers a safety intervention by the ABS Controller. Such a warning is not a fault, so would not trigger a DTC.
Sorry to waffle, but if the voltage is stable, and there no Engine, or ABS DTCs, we could simply be seeing something like left and right wheel speed differences, due to something like wheel alignment.
When you get the ABS indication, is the car in a straight line, braking, accelerating, coasting etc.
Mac.
 
Can I just recap?
When the yellow ABS light comes on, does it flash briefly, or come on steady for a while?
Does the car go into what feels like Limp Mode, at the same time, and if so, does it "reset" itself, or do you have to stop, switch the ignition off, and then restart?
Are there any other Warning, (Amber), or Alarm, (Red), lights at the same, or any other time?
Scan of Engine and ABS controllers urgently needed.
Mac.
 
Last edited:
PlasticMac said:
Can I just recap?
When the yellow ABS light comes on, does it flash briefly, or come on steady for a while?
Does the car go into what feels like Limp Mode, at the same time, and if so, does it "reset" itself, or do you have to stop, switch the ignition off, and then restart?
Are there any other Warning, (Amber), or Alarm, (Red), lights at the same, or any other time?
Scan of Engine and ABS controllers urgently needed.
Mac.
Click to expand...
Thanks Mac

This happens when driving but is hard to link to a specific repeatable thing
It seems to be after about 3 or 4 mins. It's hilly here and seems to be on uphill more than not

When I scan the engine I get the manifold baromic pressure code

Nothing else at the moment that I can recall but will check

I think it's been unable to connect the either abs controller. When I try I thinking times out. Still learning about the vdcs but I only seem to be able to scan the enfmgine controller (gendan cable + rosstech USB driver)
I've sorned the car atm so harder to test driving now but I still can move it a bit

The alarm- it comes on with 3 beeps
The small esp and abs lights - orange i think - come on
Also the large central red exclamation mark in a circle

I'll try and grab a photo today

It was then after a few mins slippingninto limp mode
That limp mode might not have happened since the battery swap

If I stop then restart it resets and I get another few mins of driving before the cycle starts again !

Any ideas why the abs controller might be timing out ?


Thanks for the help
 
yes will do Mac

i the mean time ....
just ran it again and was runnign well on the drive way and logs ok
i switched lights / heaters on and off and you can see that in the voltage drops up to about marker 4 i think
then i reved and immediately the alarm
i attach the logs and also a pic of the alarms on the dash - hopefuy better than my description!


i saw this from Sarge and wondered if this is all part of an actual manifold pressure issue but the garage did apparently do a smoe test, fouind an issue and fixed it . apparently:

S

Thread ''How to Fix' - Manifold Pressure Sensor fault'

Hi Guys my first 'how to' here, hope it helps someone.

I found that the engine light came on and after the engine (1.4i Petrol) was run for a few mins, it would either start 'hunting' (revs bouncing up & down) or turn off, this is after the autochoke went off, this would then cause a little difficulty restarting.

I did a Vag Com scan and found:
1 fault found:
17566 - Manifold Pressure Sensor (G71): Implausible signal
P1158 - 35-10 - - - Intermittent
Readiness: 1010 0101

SO I had a look around at the sensor and wiring, it all seemed to be ok, so...

I've also attached the settings i have for the vdcs setup :)

Many thanks
 

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Have you tried the pressure sensor in the intercooler ? A previous A2 had the ABS light etc and VCDS said check engine DTCs The fault turned out to be that pressure sensor. Replaced an no more alarms
 
When the engine speeds up, around marker 4, 5, is that increase in rpm you, via the accelerator, or is the engine doing it by itself?
The throttle valve opens at the same time.
Mac.
 
Last edited:
PlasticMac said:
When the engine speeds up, around marker 4, is that increase in rpm you, via the accelerator, or is the engine doing it by itself?
The throttle valve opens at the same time.
Mac.
Click to expand...
Sorry should have said... thats ne on the accelerator Mac
literally as soon as i press the accelerator the alarm went off
was idling before that with logs running
 
steveb said:
Have you tried the pressure sensor in the intercooler ? A previous A2 had the ABS light etc and VCDS said check engine DTCs The fault turned out to be that pressure sensor. Replaced an no more alarms
Click to expand...
thanks steveb
i'm not too sure where the sensor is located tbh
Is it easy to access?
Thanks
 
Because we're getting an ABS/EPC/Braking System alarm, while the car is sat on the drive, tells us it's not actually a ABS/EPC/Braking System fault, (I think).
The clue is the increase in rpm. The ESP, (Electronic Stability System), becomes active as soon as the engine speed exceeds 800 rpm, and comes out of Idle.
I think, and it's been mentioned before, that the problem we see, is due to a canbus comms failure between the ECU and the ABS controllers, as soon as the EPC is activated. The ABS controller can't communicate with the ECU, so the EPC, (Electronic Power Control), triggers Limp Mode, to limit power, as the stability gubbins is not working
We need to give the ABS Controller a cold start, by removing the fuse, (Fuse 123 40 I think), and hoping that helps. The next step would then be to clear the DTCs on the ABS controller.
The supply voltage seems to be fine.
🤞
Mac.
Edit: ABS Controller Fuse is Fuse 123, in the footwell compartment.
 
Last edited:
PlasticMac said:
Because we're getting an ABS/EPC/Braking System alarm, while the car is sat on the drive, tells us it's not actually a ABS/EPC/Braking System fault, (I think).
The clue is the increase in rpm. The ESP, (Electronic Stability System), becomes active as soon as the engine speed exceeds 800 rpm, and comes out of Idle.
I think, and it's been mentioned before, that the problem we see, is due to a canbus comms failure between the ECU and the ABS controllers, as soon as the EPC is activated. The ABS controller can't communicate with the ECU, so the EPC, (Electronic Power Control), triggers Limp Mode, to limit power, as the stability gubbins is not working
We need to give the ABS Controller a cold start, by removing the fuse, (Fuse 123 40 I think), and hoping that helps. The next step would then be to clear the DTCs on the ABS controller.
The supply voltage seems to be fine.
🤞
Mac.
Click to expand...
Ok thanks I'll have a look at the fuses a d see if I can connect to the abs controller after.
 
Last edited by a moderator:
Hers's my Comms settings:

vcdsdriverdriverdetails.pngvcdsserialportcommssetting.pngvcdsserialportcommsproperties.png
I suspect your's are the same, as I think they're the defaults with the Ross-Tech drivers.
I think the VCDS Comms is down to the controllers, not VCDS.
As well as a cold start, cleaning the connector would be worth doing.
I suppose it could be a faulty ABS Controller, but try resetting it, as the fault is intermittent.
Good info on the ABS Controller on a2-freun

Teves Mark 20 – A2-Freun.de Wiki

wiki.a2-freun.de wiki.a2-freun.de
Mac.
 
PlasticMac said:
Hers's my Comms settings:

View attachment 134507View attachment 134508View attachment 134509
I suspect your's are the same, as I think they're the defaults with the Ross-Tech drivers.
I think the VCDS Comms is down to the controllers, not VCDS.
As well as a cold start, cleaning the connector would be worth doing.
I suppose it could be a faulty ABS Controller, but try resetting it, as the fault is intermittent.
Good info on the ABS Controller on a2-freun

Teves Mark 20 – A2-Freun.de Wiki

wiki.a2-freun.de wiki.a2-freun.de
Mac.
Click to expand...
The ABS Controller, and it's fuse is in the (IUK) passenger footwell compartment. Fuse 123.
I've edited my previous post.
Mac.
Picture acknowledgments to @ajsellors

DSC04096b.jpg
 
PlasticMac said:
Because we're getting an ABS/EPC/Braking System alarm, while the car is sat on the drive, tells us it's not actually a ABS/EPC/Braking System fault, (I think).
The clue is the increase in rpm. The ESP, (Electronic Stability System), becomes active as soon as the engine speed exceeds 800 rpm, and comes out of Idle.
I think, and it's been mentioned before, that the problem we see, is due to a canbus comms failure between the ECU and the ABS controllers, as soon as the EPC is activated. The ABS controller can't communicate with the ECU, so the EPC, (Electronic Power Control), triggers Limp Mode, to limit power, as the stability gubbins is not working
We need to give the ABS Controller a cold start, by removing the fuse, (Fuse 123 40 I think), and hoping that helps. The next step would then be to clear the DTCs on the ABS controller.
The supply voltage seems to be fine.
🤞
Mac.
Edit: ABS Controller Fuse is Fuse 123, in the footwell compartment.
Click to expand...
The plot thickens !
I removed fuse 40
Turned on ignition - the traction control orange signal came on
Switched off then replaced the fuse
The traction orange symbol was off

Started the car
Reved a bit on and off for a while
No alarms
So I gave up and left it for a whilst whilst looking at vdcs to see if I could connect with any controllers

The alarm came on but this time
3 beeps + Central exclamation + abs warning in orange

The beeping went on for a few mins as I hunted for error codes. None

Then the alarm stopped

Still no error codes on engine or abs

Then the alarm came on again ( no revs from me)this time as above but also with the traction control in orange

Alarm was only on for a short while then off

Then on again!

I can't connect to the CAN gatewaywith vdcs
I can only connect to engine abs and hvac

So the fuse pull reset changed something!
The alarm seems unconnected with revs now

I don't think its gone into limp as I could still rev throughout

I'm not sure how the computer onboard is configured but assume the canbus is central comms ? So not being able to connect tonit is odd

Again no error codes in any of rhe controllersnj can connect too
Progress of sorts !?
Many thanks
 
Something is upsetting the CANBUS.
I suspect ABS, EPC, but it could be anything.
Any CANBUS gurus here?
Mac.
 
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