Error Clearing Not Working? Troubleshooting Guide.

I had the diagnostic codes read on my colleague's 2005 TT 8N because the MIL (Malfunction Indicator Lamp) was illuminated on his car.
The following error message appeared:

"1 error found:"

16885 - Vehicle speed signal.

P0501 - 35-10 - Implausible signal - Intermittent.



The attempt to clear the error memory failed because the software indicates that it is not possible to establish communication with the control unit.



Does anyone with expertise perhaps know what might be causing this?



I don't want to know anything about the error itself, but rather how to clear the error memory.

Are you trying to clear the error directly from the vehicle's diagnostic scan or directly within the individual control unit?

The easiest way to post is to include a complete car scan.

I'm not sure where the speed signal originates from in the TT. It's probably coming from either the instrument cluster or the ABS system.
The MIL (Malfunction Indicator Lamp) from the engine control unit is just a symptom. That means clearing the error codes in the engine control unit will not fix the problem. The error must be cleared at the source.

Regards,
Guste.

Hi,

Without a scan, it's just guesswork.

One possible reason for the failure of communication between engine control units (ECUs) could be the central vehicle (CV) system.

Was the fire door open on all doors during the firefighting attempt?

I'll assume that a sufficient power supply in the form of a high-quality charger is already available.


Greetings.

Thank you for the answers.
I had the driver's door open during the reading and clearing process, but I will try it again later with the doors closed.
If that was the reason why the error wasn't cleared, then that was a very helpful hint.
Okay, please provide the German text you want me to translate. I will provide the English translation without any explanations.
"Just a quick question: What more can be read from the entire scan compared to the essential part with the error message? I'm asking this to learn more about the OBD system."




Thursday, January 21, 2021, 11:50:09:24743
VCDS -- A VAG/VAS emulator based on Windows, running on Windows 10 x64.
VCDS Version: DRV 20.4.2.1 HEX-V2 CB: 0.4529.4
Data as of: 20201124 DS317.0
shop.dieselschrauber.org


Vehicle Identification Number: License Plate: RATT8N DIEZWEITE
Mileage: 166,840 km. Repair order:



"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."


Vehicle type: 8N (8N - Audi TT (1999 > 2007))
Scan: 01 02 03 08 15 17 22 35 37 45 55 56 76 77

Vehicle Identification Number:
Mileage: 166,840 km
"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
Address 01: Engine Control Module
Label file: DRV\06A-906-032-AJQ.clb
Part number: 8N0 906 018 BR
Component: 1.8L R4/5VT 0001
Encoding: 11500
Operating number: WSC 01236
VCID: 025C7F60CD191B6B446-5118
TRUZZZ8N141019308 AUZ5Z0CD035120

"One error found:"
16885 - Vehicle speed signal.
P0501 - 35-10 - Implausible signal - Intermittent.
Readiness: 0000 0000

"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
Address 03: Brake Electronics Label file: DRV\8N0-907-379-MK60-F.lbl
Part number: 8N0 907 379 J
Component: ESP FRONT MK60 0101
Encoding: 0019469
Operating number: WSC 01236 785 00200
VCID: 43D2BA649783D2630F0-5118

No error codes found.

"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
Address 08: Climate Control/Heating. Label file: DRV\8N0-820-043.lbl
Part number: 8N0 820 043 A
Component: TT CLIMATE CONTROL FULL AUTOMATIC SYSTEM D03.
Encoding: 00040
Operating number: WSC 01236
VCID: 28080DC80BE5113B3A2-2578

No error codes found.

"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
Address 15: Airbag
Label file: DRV\8N0-959-655.lbl
Part number: 8N0 959 655 D
Component: Front and Side Airbag 0000
Encoding: 01102
Operating number: WSC 01236
VCID: 41DEB06C889FC0731DC-5118

No error codes found.

"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
Address 17: Control panel module
Label file: DRV\8Nx-920-xxx-17.lbl
Part number: 8N1 920 930 Q
Component: COMBINATION INSTRUMENT + SPEEDOMETER. M73 D14
Coding: 00044
Operating number: WSC 76112
VCID: 3FDAB694FE6BB6836B8-4AE0
TRUZZZ8N141019308 AUZ5Z0CD035120

No error codes found.

"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
Address 35: Central Locking
Label file: DRV\8Nx-962-267.lbl
Part number: 8N7 962 267 D
VCID: 41DEB06C889FC0731DC-4EEA

No error codes found.
or error codes are not supported by the control unit.
or communication errors occurred.

"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
Address 55: Headlight range control. Label file: DRV\4B0-907-357-AUT.lbl
Part number: 4B0 907 357.
Component: LIGHT DIMMER D004
Coding: 00009
Operating number: WSC 01236
VCID: 659644FC3C77CC53C14-513C

No error codes found.

"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
Address 56: Radio
Label file: DRV\8E0-035-1xx-56.lbl
Part number: 4B0 035 186 S
Part: concert II GRO 0001
Encoding: 00200
Operating number: WSC 01236
VCID: 3038E5A8333559FBE22-4AE0

No error codes found.

End--(Duration: 02:47, Battery Voltage Start/End: 11.8V/11.8V. VIgn 11.8V)---

Hello,

It is important to ensure that the central locking system is unlocked on both doors.

11.8 volts is also a bit low as an onboard voltage.

Good luck.

Hi.

char032 wrote:

[Just a quick question: What more can be read from the entire scan compared to the essential part with the error message? I'm asking this to learn more about the OBD system.]

Which control units have which errors, voltage of the vehicle's electrical system, ignition status, etc.

In general, errors cannot be cleared if the corresponding control unit is not active during the clearing process (ignition off, sleep mode, etc.), if the on-board voltage is too low, if the control unit is defective or contains an unsuitable data set, or if the error still persists.
A persistent error is either only temporary or never truly removable.

Best regards, Rainer.

Address 35: Central locking
Label file: DRV\8Nx-962-267.lbl
Part number: 8N7 962 267 D
VCID: 41DEB06C889FC0731DC-4EEA

No error codes found.
or error codes are not supported by the control unit.
or communication errors occurred.


Something is also wrong here. First, ensure a sufficient power supply of approximately 12.4V before proceeding.

Thank you for the helpful suggestions.
Today, the error clearing process worked with all doors closed.
MIL has not been illuminated so far.
Let's see how things unfold.