Hello As I have already marked in the subject, I have a red brake light with the word "brakes". After inserting the key and turning the ignition switch, after 2-5 seconds the "brakes" indicator light and 3 beeps appear. The car cannot be started. After turning the ignition key, nothing happens (except for the "brakes" light and various other controls). One day, when I was going for shopping at the roundabout, my car went out and the aforementioned light came on. After waiting for about 5 minutes, the car fired up normally and nothing happened. The second time the indicator appeared when I was returning from the store. After checking the VCDS errors, it turned out that some other errors were not related to the brakes at all. (then I had 3 errors about the fuel flap lock and some two about air conditioning or ivh fans) The brakes have been checked by a mechanic, brake fluid checked and topped up (if there were any deficiencies) After two weeks, the same appeared, but this time it showed other errors than the last one. Today the car has not started at all. When the key is turned, only the brake indicator light is on. After checking the errors in the past, it turned out that the errors arrived, most of them were described as "can't be reached" Could the problem be the Akumylator? Each time I check with a multimeter, it shows 12.33V (I think this is a good result, unless the electronics are very sensitive and must have 12.5V-12.6V) Anyone have any knowledge about this? When I had the lapop connected to the car, there was an error with the lack of fuel, the fuel control dropped to zero. (After erasing errors, it returned to normal) Is the ECU (driver) damaged? Does anyone know how to check it? how to test what? Thanks in advance. I hope someone can help me solve it.
The fuse box is ok. It is not wet, there is no rust. The cable connections do not drown out. Everything looks fine in the fuse box under the hood. Tomorrow I will try to dismantle the pit. Could you explain how to check the power supply of the drivers? Thanks
Little update: Today the battery was 12.13V, which is even less than yesterday. It is exactly the same as yesterday. The weight is okay (checked with a mutimeter). If I manage to download the wipers, I will insert pictures of the ECU. Greetings.
I would rule out aku. At least I was riding on unloaded and it was ok.
In my case, such a situation with the controls appears when there is, for example, a slippery road and the car is "nailed". (altogether dry also when I press the gas harder) Or I will stand on the side of the road with the other on the asphalt and let the gas go to the limit. Do you have a DSG or a manual? Recently it started to appear more often. And the inspection revealed that the joint has a lot of play. I haven't mentioned it yet, so I don't know if the joint has anything to do with it. I will let you know if I change or get better. In general, I have the impression that these lights flash in my car when one wheel loses grip (in relation to) the other (I do not know if I expressed myself well) My car has never gone out because of this. . Greetings If you have vcdsa, you can scan can. Maybe he'll show something.
Hello Today I replaced a brand new battery with 12.45V and the same thing happened. After connecting to VCDS, a lot of errors again. Most of them say that the given sensor "can't be reached" Tomorrow I will check all the fuses under the hood and those on the side of the door (passenger or driver?) Do you have any inventory where all the grounding points are in the audi a3 8p? Thanks in advance.
The fuses are from the driver and under the hood, check the big ones too (I think 200A goes for the alternator, etc.). It would be nice to also check the relays. You don't have any immobilizer error? How can you then post these bugs to see them. Maybe someone will notice something wrong. The strange thing is that it won't fire.
W dniu dzisiejszym posprawdzalem wszystkie bezpieczniki obok akumulatora ( wszystkie sprawne).
Odkrecilem tez ten plastik na ktorym siedzi akumulator aby sprawdzic kable pod nim. Vizualnie wygladaja dobrze( nie ma zandych przypalen albo czarnych stopien)
Masa ktora idzie na skrzynie wyglada troche rudo( jutro do przeczyszczenia )
Bledy ponizej:
VCDS Version: Release 12.12.0
Data version: 20130910
00796 - Fan for Interior Temp Sensor (V42)
011 - Open Circuit
Freeze Frame:
Fault Status: 01101011
Fault Priority: 3
Fault Frequency: 1
Reset counter: 152
Mileage: 254314 km
Time Indication: 0
Date: 2017.11.07
Time: 00:01:18
Freeze Frame:
Voltage: 12.40 V
Temperature: 9.0°C
01592 - Air Quality Sensor (G238)
010 - Open or Short to Plus
Freeze Frame:
Fault Status: 01101010
Fault Priority: 3
Fault Frequency: 6
Reset counter: 152
Mileage: 254287 km
Time Indication: 0
Date: 2017.10.28
Time: 13:10:47
Freeze Frame:
Temperature: -50.0°C
01206 - Signal for Duration of Ignition Off Time
008 - Implausible Signal
Freeze Frame:
Fault Status: 01101000
Fault Priority: 3
Fault Frequency: 1
Reset counter: 152
Mileage: 254314 km
Time Indication: 0
Date: 2017.11.07
Time: 00:03:49
Freeze Frame:
-------------------------------------------------------------------------------
Address 09: Cent. Elect. Labels: 8P0-907-279-30-H.lbl
Part No SW: 8P0 907 279 K HW: 8P0 907 279 K
Component: Bordnetz-SG H54 2501
Revision: 00H54000 Serial number: 00000008016051
Coding: 01880F01B01410004F1600001600000000085E175C010000000000000000
Shop #: WSC 06314 000 08192
VCID: 4581B79F0C543D36E75-8010
4 Faults Found:
00849 - S-contact at Ignition/Starter Switch (D)
008 - Implausible Signal - Intermittent
00332 - Control Circuit for Tank Flap
007 - Short to Ground - Intermittent
00625 - Vehicle Speed Signal
004 - No Signal/Communication
01321 - Control Module for Airbags (J234)
004 - No Signal/Communication
-------------------------------------------------------------------------------
Address 47: Sound System Labels: 8Px-035-382.lbl
Part No SW: 8P4 035 382 D HW: 8P4 035 382 D
Component: AB2 SUBWOOFERBOXH06 0180
Revision: 00005 Serial number: 30674753093803
Shop #: WSC 00000 000 00000
VCID: 3561C75F5CB4ADB6775-8060
No fault code found.
-------------------------------------------------------------------------------
Address 52: Door Elect, Pass. Labels: 1K0-959-702-MIN3.lbl
Part No SW: 8P0 959 802 K HW: 8P0 959 802 K
Component: Tuer-SG H03 0050
Coding: 0000688
Shop #: WSC 06314 000 00000
VCID: 4487AA9B076E043EF0B-8011
2 Faults Found:
00929 - Locking Module for Central Locking; Front Passenger Side (F221)
008 - Implausible Signal
01321 - Control Module for Airbags (J234)
004 - No Signal/Communication
-------------------------------------------------------------------------------
Address 56: Radio Labels: 8J0-035-1xx-56.clb
Part No SW: 8P0 035 186 P HW: 8P0 035 186 P
Component: R Concert2+ H01 0270
Revision: 00H01000 Serial number: AUZ1Z3G8398627
Coding: 0110211
Shop #: WSC 06314 000 00000
VCID: 3F8DA5776E8867E6AD9-806A
No fault code found.
-------------------------------------------------------------------------------
Address 62: Door, Rear Left Labels: 8P4-959-801.lbl
Part No SW: 8P4 959 801 E HW: 8P4 959 801 E
Component: Tuer-SG H04 0040
Coding: 0000144
Shop #: WSC 06314 000 1012544
VCID: 4189A38F187C1116DBD-8014
No fault code found.
-------------------------------------------------------------------------------
Address 72: Door, Rear Right Labels: 8P4-959-802.lbl
Part No SW: 8P4 959 802 E HW: 8P4 959 802 E
Component: Tuer-SG H04 0040
Coding: 0000144
Shop #: WSC 06314 000 1012544
VCID: 428BAC831D7A0A0EC27-8017
No fault code found.
End ---------------------------------------------------------------------
I do not know what to say . It looks like there are no connections between the modules, no voltage supplied to the modules.
If it were my car, I would start my search from the comfort module. It's in the trunk (if you're facing the trunk, it's on the right)
Remove the mat from the bottom of the trunk remove the plastic holding the warning triangle in the trunk of the trunk There is also a screw to unscrew somewhere at the top. Then you fold back the trunk lid. And you'll get to the module, such a little black cube. Tip no. module is probably - 433. but I am not sure, I do not remember. It's so you know which one it is. Detach the module. See what will happen.
This error is interesting. Address 16: Steering wheel Labels: 8P0-953-549-F.lbl Part No SW: 8P0 953 549 F HW: 8P0 953 549 F Component: J0527 H36 0070 Coding: 0000042 Shop #: WSC 06314 000 00000 VCID: 4189A38F187C1116DBD-8014
1 Fault Found:
Code: Text
Log in, to see the code
Maybe there is something wrong in the ignition switch. You will have a lot of fun and checking.
The fuses are from the driver and under the hood, check the big ones too (I think 200A goes for the starter, etc.). It would be nice to also check the relays. You don't have any immobilizer error? How can you then post these bugs to see them. Maybe someone will notice something wrong. The strange thing is that it won't fire.
And since when is the starter working lead secured with a fuse?
Udalo mi sie rozwiazac problem z uruchomieniem auta. Byl to przekaznik z numerem 460 na gorze usytulowany pod kierownica. Byly tam dwa takie same przekazniki to zamienilem je miejscami tymczasowo. Teraz musze sie rozprawic z reszta problemow. Dalej mam ikonke breaks na dashbordzie. Czy ktos wie Od czego wywala te przekazniki ? Zwarcia ? Brak masy ?
Update jezeli chodzi o bledy:
VCDS Version: Release 12.12.0
Data version: 20130910
00796 - Fan for Interior Temp Sensor (V42)
011 - Open Circuit
Freeze Frame:
Fault Status: 01101011
Fault Priority: 3
Fault Frequency: 1
Reset counter: 152
Mileage: 254314 km
Time Indication: 0
Date: 2017.11.07
Time: 00:01:18
Freeze Frame:
Voltage: 12.40 V
Temperature: 9.0°C
01592 - Air Quality Sensor (G238)
010 - Open or Short to Plus - Intermittent
Freeze Frame:
Fault Status: 00101010
Fault Priority: 3
Fault Frequency: 6
Reset counter: 192
Mileage: 254287 km
Time Indication: 0
Date: 2017.10.28
Time: 13:10:47
Freeze Frame:
Temperature: -50.0°C
-------------------------------------------------------------------------------
Address 09: Cent. Elect. Labels: 8P0-907-279-30-H.lbl
Part No SW: 8P0 907 279 K HW: 8P0 907 279 K
Component: Bordnetz-SG H54 2501
Revision: 00H54000 Serial number: 00000008016051
Coding: 01880F01B01410004F1600001600000000085E175C010000000000000000
Shop #: WSC 06314 000 08192
VCID: 4581B79F0C543D36E75-8010
3 Faults Found:
00156 - Control Circuit for Windshield Washer Pump
009 - Open or Short to Ground
Freeze Frame:
Fault Status: 01101001
Fault Priority: 3
Fault Frequency: 1
Reset counter: 152
Mileage: 254314 km
Time Indication: 0
Date: 2017.11.07
Time: 00:52:00
Freeze Frame:
ON
Voltage: 11.65 V
OFF
ON
OFF
OFF
OFF
02398 - Control Circuit for Rear Windshield Washer Pump
009 - Open or Short to Ground
Freeze Frame:
Fault Status: 01101001
Fault Priority: 3
Fault Frequency: 1
Reset counter: 152
Mileage: 254314 km
Time Indication: 0
Date: 2017.11.07
Time: 00:52:00
Freeze Frame:
ON
Voltage: 11.65 V
OFF
ON
OFF
OFF
OFF
-------------------------------------------------------------------------------
Address 47: Sound System Labels: 8Px-035-382.lbl
Part No SW: 8P4 035 382 D HW: 8P4 035 382 D
Component: AB2 SUBWOOFERBOXH06 0180
Revision: 00005 Serial number: 30674753093803
Shop #: WSC 00000 000 00000
VCID: 3561C75F5CB4ADB6775-8060
No fault code found.
-------------------------------------------------------------------------------
Address 52: Door Elect, Pass. Labels: 1K0-959-702-MIN3.lbl
Part No SW: 8P0 959 802 K HW: 8P0 959 802 K
Component: Tuer-SG H03 0050
Coding: 0000688
Shop #: WSC 06314 000 00000
VCID: 4487AA9B076E043EF0B-8011
1 Fault Found:
00929 - Locking Module for Central Locking; Front Passenger Side (F221)
008 - Implausible Signal
-------------------------------------------------------------------------------
Address 56: Radio Labels: 8J0-035-1xx-56.clb
Part No SW: 8P0 035 186 P HW: 8P0 035 186 P
Component: R Concert2+ H01 0270
Revision: 00H01000 Serial number: AUZ1Z3G8398627
Coding: 0110211
Shop #: WSC 06314 000 00000
VCID: 3F8DA5776E8867E6AD9-806A
No fault code found.
-------------------------------------------------------------------------------
Address 62: Door, Rear Left Labels: 8P4-959-801.lbl Part No SW: 8P4 959 801 E HW: 8P4 959 801 E Component: Tuer-SG H04 0040 Coding: 0000144 Shop #: WSC 06314 000 1012544 VCID: 4189A38F187C1116DBD-8014
No fault code found.
-------------------------------------------------- ----------------------------- Address 72: Door, Rear Right Labels: 8P4-959-802.lbl Part No SW: 8P4 959 802 E HW: 8P4 959 802 E Component: Tuer-SG H04 0040 Coding: 0000144 Shop #: WSC 06314 000 1012544 VCID: 428BAC831D7A0A0EC27-8017
No fault code found.
End ------------------------------------------------- --------------------
All problems solved. I cleaned the plug from the brake fluid level sensor and I have no control on the dash. As of today, everything has been solved. In the foreground, I could use the wiring diagram for the Audi A3 8p but I couldn't find it anywhere. After the scheme it would be easy and quick to get what, where. Thanks to everyone for your help.
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✨ The discussion revolves around a 2007 Audi A3 8P experiencing a persistent red brake light warning and inability to start. The owner reports that the brake indicator activates after turning the ignition, accompanied by beeping sounds, and the vehicle fails to start. Initial troubleshooting included checking the brake system, battery voltage, and VCDS error codes, which revealed multiple communication errors with various modules. Suggestions from other users included inspecting the battery connections, fuse box, and grounding points. The owner eventually identified a faulty relay under the steering column, which resolved the starting issue, but the brake warning light remained. Further investigation into the cause of the relay failure is ongoing. Generated by the language model.
TL;DR: Audi A3 8P with red "BRAKES" and 3 beeps, no crank? The fix was swapping/replacing relay 460; "It was relay 460 under the steering wheel." [Elektroda, brayanek7, post #16814160]
Why it matters: This FAQ helps 2003–2012 A3 8P owners quickly diagnose no‑start with a red brake lamp.
My Audi A3 8P shows a red “BRAKES” light with 3 beeps and won’t crank—what fixed it in this thread?
Swapping identical relay 460 units under the steering wheel restored cranking and CAN communication. Replacing the faulty 460 relay resolved the no‑start. The brake warning then cleared after cleaning the brake fluid level sensor connector. “It was relay 460 under the steering wheel.” [Elektroda, brayanek7, post #16814160]
Does a low battery cause this A3 8P no‑start with brake lamp?
No. The owner installed a brand‑new 12.45 V battery, yet the car still would not start, and many modules were unreachable on VCDS. The underlying issue was the 460 relay, not the battery state. Battery voltage alone did not resolve the fault. [Elektroda, brayanek7, post #16810159]
Which fuses and relays should I check first?
Check the driver‑side interior fuse panel and the under‑hood fuses, then inspect the relays under the steering wheel. Pay special attention to relay 460 if you have no‑crank plus widespread communication errors. Inspect and reseat high‑amperage fuses as well. [Elektroda, TOMEKELE, post #16811204]
What is the ‘460’ relay on the Audi A3 8P and where is it?
It’s a power supply relay located under the steering wheel in the relay carrier. In the case described, two identical 460 relays were present; swapping them proved one was faulty. Replacing that relay restored normal starts and module communication. [Elektroda, brayanek7, post #16814160]
VCDS shows many modules “Cannot be reached.” What does that indicate?
It indicates a widespread power or communication problem affecting multiple control units. In the thread, this cleared after the 460 relay swap, confirming a power distribution fault. Statistic: 6 core modules were initially unreachable. [Elektroda, brayanek7, post #16812259]
What does the CAN bus do on the A3 8P?
The CAN bus is the car’s data network linking modules. The scan showed “00470 - Combination comfort Databus in Single Wire – Open Circuit,” signaling a communication path issue that coincided with the power relay fault in this case. [Elektroda, brayanek7, post #16812259]
How do I clear the red brake warning after fixing the no‑start?
Clean the brake fluid level sensor connector at the reservoir. In this case, removing oxidation on that plug cleared the red brake lamp on the cluster without further parts. It remained off after normal driving. [Elektroda, brayanek7, post #16814160]
Could water ingress or bad grounds cause similar symptoms?
Yes. Members advised checking the under‑hood fuse box for moisture and verifying main ground straps. Corroded grounds or wet fuse boxes can create intermittent power losses that mimic module faults and inhibit starting. [Elektroda, jenusz11, post #16801314]
Where is the comfort module (KSG) on the A3 8P?
It’s in the trunk on the right side behind the liner. Remove the trunk floor mat, the plastic trim with the triangle, and the upper fastener to pull the side panel back and access the module. [Elektroda, TOMEKELE, post #16813396]
Is the immobilizer the reason it won’t start when the brake lamp shows?
Not in this case. VCDS showed the immobilizer status as OK while the vehicle would not crank. The root cause was a failed 460 relay and a dirty brake fluid sensor connector. The immobilizer logged no fault. [Elektroda, brayanek7, post #16812259]
I see a ‘Terminal 75x – Electrical Fault in Circuit’ code. What happened here?
That code appeared during the widespread power issue. After the relay 460 was swapped and power was restored, later scans no longer showed it. This ties it to the relay-related power loss rather than a permanent wiring defect. [Elektroda, brayanek7, post #16814160]
How can I quickly triage this fault at home?
Use this 3‑step triage:
Scan with VCDS and save the autoscan.
Inspect/clean the brake fluid level sensor connector.
My wipers and washer pumps show circuit faults after a no‑start—related?
Yes, they can appear as side‑effects of low or interrupted switched power. The scan showed washer circuit faults alongside the power issue; these cleared once the relay problem was fixed and voltage stabilized at the modules. [Elektroda, brayanek7, post #16814160]
Should I replace the ECU if I see many communication errors?
No. Diagnose power and relays first. Despite multiple “Cannot be reached” errors, the engine ECU was fine after restoring power via the 460 relay swap. Quote: “All problems solved.” [Elektroda, brayanek7, post #16814160]
Which observations help separate battery issues from relay faults?
A fresh 12.45 V battery did not change the no‑start, and modules still failed to respond. That points away from capacity and toward distribution. Consistent with this, replacing the 460 relay restored full module communication. [Elektroda, brayanek7, post #16810159]
Edge case: can the car stall mid‑drive and then restart later with this fault?
Yes. The owner reported a stall at a roundabout and a restart after five minutes. Intermittent relay failure can cause sudden power loss and temporary recovery as contacts cool. [Elektroda, brayanek7, post #16801226]
