Brake switch implausible signal

So here is the first scan:

Address 01: Engine Labels: 045-906-019-AMF.LBL
Controller: 045 906 019 G
Component: 1,4l R3 EDC 0000SG 1281
Coding: 00002 Shop #: WSC 02138
2 Faults Found:
16955 - Brake Switch (F): Implausible Signal P0571 - 35-00 - -
17571 - Shareware Version. To Decode all DTCs P1163 - 35-10 - Please Register/Activate - Intermittent Readiness: N/A
-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: None
Controller: 8Z0 907 379 B
Component: ESP 20 CAN V015
Coding: 10758 Shop #: WSC 02154 VCID: 47E1D81F76B5
No fault code found

And here is the scan after clearing the Engine and ABS ECUs (no change):

Address 01: Engine Labels: 045-906-019-AMF.LBL
Controller: 045 906 019 G
Component: 1,4l R3 EDC 0000SG 1281
Coding: 00002 Shop #: WSC 02138
2 Faults Found:
16955 - Brake Switch (F): Implausible Signal P0571 - 35-00 - -
17571 - Shareware Version. To Decode all DTCs P1163 - 35-10 - Please Register/Activate - Intermittent Readiness: N/A
-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: None
Controller: 8Z0 907 379 B
Component: ESP 20 CAN V015
Coding: 10758 Shop #: WSC 02154 VCID: 47E1D81F76B5
No fault code found

I will scan again tomorrow after driving it, though I suspect it will be much the same. The two codes on the engine ECU do not clear when I attempt to clear them in VCDS.

I had the passenger side footwell compartment open yesterday and it was completely dry in there, all electrics look dry and clean and no evidence of moisture anywhere.

No work has been carried out on the car by myself or anyone else. I do remember the exact moment the glow plug light started flashing, I was driving around a corner having just slowed down.

I have noticed the glow plug light starts flashing at the same time as a whiring sound from the centre of the car, assume this is the ABS pump. Not sure if that's relevant.

I have also just tested my original switch again with a multi-meter, and it is definitely working correctly. I did take this apart a couple of weeks ago and cleaned it out, there was a dark mark on one of the contacts, again, not sure if that's normal after 21 years of use or if it points to something in particular.
 
Nothing glaringly obvious there.

17571 is the fuel temp sensor has an error.

How did you clear the errors? By just pressing the clear dtc codes button, or did you go into each module individually then clear the codes there as quite often with the shareware version that is the best way to clear the codes.

You mentioned the error occured after driving around a corner and slowing down. This could be an issue in the ABS system or the stability system that includes the steering wheel clock spring and the lateral accelerometer.
 
audifan said:
Nothing glaringly obvious there.

17571 is the fuel temp sensor has an error.

How did you clear the errors? By just pressing the clear dtc codes button, or did you go into each module individually then clear the codes there as quite often with the shareware version that is the best way to clear the codes.

You mentioned the error occured after driving around a corner and slowing down. This could be an issue in the ABS system or the stability system that includes the steering wheel clock spring and the lateral accelerometer.
Click to expand...
On vcds lite, (licensed or not), there is no clear DTC button, you can only clear each error via controller > errors > clear DTC. So @LordTJC could only have cleared them one at a time.
Wondering if error is abs related, but coming up as brake switch. Brake switch and abs are directly related.
Mac.
 
PlasticMac said:
On vcds lite, (licensed or not), there is no clear DTC button, you can only clear each error via controller > errors > clear DTC. So @LordTJC could only have cleared them one at a time.
Wondering if error is abs related, but coming up as brake switch. Brake switch and abs are directly related.
Mac.
Click to expand...
As is the stability systems.


Been MANY years since I have used Lite
 
I have been going into each ECU in VCDS Lite to clear the codes.

This is the scan result after driving:

Address 01: Engine Labels: 045-906-019-AMF.LBL
Controller: 045 906 019 G Component: 1,4l R3 EDC 0000SG 1281
Coding: 00002 Shop #: WSC 02138
3 Faults Found:
16955 - Brake Switch (F): Implausible Signal P0571 - 35-00 - -
17571 - Shareware Version. To Decode all DTCs P1163 - 35-10 - Please Register/Activate - Intermittent
17552 - Shareware Version. To Decode all DTCs P1144 - 35-00 - Please Register/Activate Readiness: N/A

There were no codes on the ABS ecu. I have tried clearing the ABS ecu first and then the engine ECU and this didn't change anything (also when there was an ABS code previously I tried clearing that first).

The brake lights are still working perfectly fine. I notice a couple of LEDs in the high level light aren't working. Would the high level light cause this brake switch issue if it went bad? Though I think I read somewhere it is on a different circuit?

I will re-read the whole thread but I can't think of anything else to try at this stage.
 
You have three DTCs, P0571, P1163, and P1144. I've pasted in the Ross-Tech notes for each.
The second and third relate too fuelling.
One possible cause of the first (P0571) is: Malfunction Indicator Lamp (MIL) active/Glow Plug Indicator Light active.
Could the fuelling be casing a MIL or Glow Plug fault? Maybe a Glow Plug Light fault (check if the Glow Plug Light comes on at startup).
Maybe investigate those Fuelling/Glow Plug Light DTCs first, and ignore the P0571 for now? Would make a change of focus.
Mac.

16955/P0571/001393 - Brake Light Switch (F): Implausible Signal​

Possible Symptoms​

  • Malfunction Indicator Lamp (MIL) active
  • Glow Plug Indicator Light active
  • Brake Light(s) not working

Possible Causes​

  • Wiring and/or Connectors faulty
  • Fuse(s) faulty
  • Wrong Brake Light Bulb installed (21W instead of 5/21W)
  • Brake Light Bulb(s) faulty
  • Brake Light Switch (F) faulty

Possible Solutions​

  • Check Wiring or Connectors
  • Check/Replace Fuse(s)
  • Check/Replace Brake Light Bulb(s)
  • Check/Replace Brake Switch (F)

17571/P1163/004451 - Fuel Temp Sensor (G81): Open or Short to Plus​

Possible Symptoms​

  • Fuel consumption higher then normal
  • Starting the engine is not as easy as normal
  • Emission Levels not met

Possible Causes​

  • Wiring/Connectors from/to Fuel Temp Sensor (G81) faulty
  • Fuel Temp Sensor (G81) faulty

Possible Solutions​

  • Check/Repair Wiring/Connectors from/to Fuel Temp Sensor (G81)
  • Check/Repair Fuel Temp Sensor (G81)

17552/P1144 - Mass Air Flow Sensor (G70): Open or Short to Ground​

Possible Symptoms​

  • MIL on
  • Excessive smoke from Exhaust
  • Reduced Engine Output

Possible Causes​

  • Fuse or Wiring Harness Issue
  • Failed Mass Air Flow Sensor (G70)


Possible Solutions​

  • Check Fuses and Wiring Harness, see Factory Repair Manual
  • Replace Mass Air Flow Sensor (G70)
  • Check Measuring Value Blocks
  • Check EGR with TDI engines
 
Now is the time to put the car into a good garage and let them sort it. We have explained what the fault codes are but nothing has been resolved. There is now a high chance of you being lead down the rabbit hole with incorrect assumptions on the fault codes. Collectively we have saved you hundreds on diagnostics and mechanics times so now spend some money with professionals who can actually put their hands on the car and see exactly what is going on with it. The tdi engines are also peculiar with the way they display errors and are unlike the petrol engines.

Now is also probably the time to draw a line under this whole thread and close it down.

Come back with another thread with the success story.
 
HI All
I'm assuming that the engine check light is on? Looks like there is a common fault there, the MIL light is on caused by the MAF fault code 17552 (G70 sensor). With this fault your car might fail the MOT on emissions.
If i'm reading this correctly once the MAF code is cleared the brake light switch implausible signal might clear.
P1144 Possible faults that will bring up this code are Faulty MAF sensor, throttle system errors and possible vacuum leaks.
Is there anyone close to you with an AMF engine A2 that you could swap maf sensors to try?
If not then i also second a visit to a vw/audi specialist garage.
Best of luck
Steve
 
Hi all
Not sure what the resolution was for @LordTJC however for others who get here searching "implausible Signal", I had an EPC light come up on a 1.4 Petrol when I changed the bulbs to LED ones. The error was the same. I had to change back to standard bulbs AND clear the error using VCDS lite to get the EPC warning to stop.
Perhaps losing too many LEDs on the centre strip may have an effect here.
From the huge amount of work done by LordTJC, I doubt this is his problem, but there is a sensitivity with the brake lights.........

Matt
 
Last edited:
Oskar said:
Hi all
Not sure what the resolution was for @LordTJC however for others who get here searching "implausible Signal", I had an EPC light come up on a 1.4 Petrol when I changed the bulbs to LED ones. The error was the same. I had to change back to standard bulbs AND clear the error using VCDS lite to get the EPC warning to stop.
Perhaps losing too many LEDs on the centre strip may have an effect here.
From the huge amount of work done by LordTJC, I doubt this is his problem, but there is a sensitivity with the brake lights.........

Matt
Click to expand...
The ECU monitors the voltage change when the brake light goes on. Because the led takes so little current, the voltage change is to low to convince the ECU that it's on.
Mac.
 
Last edited:
Ah I forgot to post the solution. The ECU was faulty (as I suspected after nothing else discussed worked) and was rebuilt. No more blinking light! Particular thanks to @PlasticMac for spending so much time researching the wiring diagrams to help with this. I hope to get a few more years out my my A2 having spent more than its value on repairs since March!

Tim
 
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