Non starting, Brake light on

**Bob Heritage** · 27-07-2020,08:38 AM

Hi, 2008 A3 1.4. Will not start and brake light on. AA called out, he disconnectd battery and reconnected again-no difference. Suggested dirty terminals to ECU. Disconnected cables, sprayed contact cleaner and reassembled. No difference immediately but started next day with no faults reading. This has now happened again after 1 week. Any suggestions, Thanks in advance.

**Roverfan** · 27-07-2020,10:08 AM

Originally Posted by Bob Heritage

Hi, 2008 A3 1.4. Will not start and brake light on. AA called out, he disconnectd battery and reconnected again-no difference. Suggested dirty terminals to ECU. Disconnected cables, sprayed contact cleaner and reassembled. No difference immediately but started next day with no faults reading. This has now happened again after 1 week. Any suggestions, Thanks in advance.

Does it crank?
If not check brake switch and clutch master cylinder circuits. First thing to check would be to pull the plugs off for any possible overheating

**Bob Heritage** · 27-07-2020,06:42 PM

Thanks for your suggestion, I will try that tomorrow, ( No it doesn't crank, completely dead apart from dash lights)

**malt56** · 27-07-2020,07:32 PM

Could immobiliser be getting engaged ? Is there fuel in the tank ? On a Mazda I had - the fuel pump packed in - so no fuel getting to engine.

**fourringsrus** · 27-07-2020,07:44 PM

Usually when your battery is on its way out you will get the big red brake fault symbol.Its Audis way to suggest that there is a problem with the brakes, thus ensuring you dont drive the car until professional investigation.
You naturally check your pads/discs/fluid etc and find nothing wrong and carry on driving the car,A short time on you get starting irregularities and then non starting, battery finished.
The reason they dont want you to drive with a weakening battery is because of all the cars various safety systems which rely on a perfectly working electrical system.
I am surprised the AA man did no checks on the battery condition rather than assuming ECU issues.
Look, if this sends you up the wrong path and you do in fact have other issues Im sorry I couldnt help this time but it is a commonly known thing in the Audi owners world, good luck

Stuart

**fourringsrus** · 27-07-2020,07:48 PM

I just read the original post again and am sure you battery is finished or not being fully recharged,battery dud or circuit not charging
Good luck

Stuart

**Roverfan** · 27-07-2020,09:30 PM

Must admit I am favouring the suggestion of Stuart over what I said earlier. I confused brake light (dash) for rear brake lights (a symptom which can inhibit starter operation)

**Bob Heritage** · 27-07-2020,10:53 PM

Thanks again for your suggestions, The battery is only a couple of months old, Exide 4yr warrenty, I did put jump leads on it just in case something was wrong, but no change. Probably a connection somewhere as it sprang back into life for a week last time.

**Bob Heritage** · 01-08-2020,10:17 PM

Update on my daughters A3. Today I have dismantled feeds to ECU again and sprayed contact cleaner on them and recharged the battery to full. I have also had a scan reader plugged in but it was unable to read/make contact. Do you think it could be a faulty ECU, if so ,can they be repaired? (Central locking works fine) Also any advise on system readers and which one to buy? can they be bought second hand.
Thanks again.

**malt56** · 02-08-2020,05:53 PM

I bought a reader from ebay - not cheap £60 - the one I got suited my car - This is the link - maybe check if there is a system reader for your car from vendor
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