Brake light warning came on after brief spirited driving

[Mechcanico Lee]

Can you see the fluid level in the resvoir, the accelerating away quickly and it flashing on does sound a bit like fluid level thing .

With regards to the battery regulation , go into the battery regulation module and go into data blocks look for s.o.c .... state of charge ,with engine running see what the percentage is and post up .

[Johnmed]

Thanks for that Lee.

Ok. Fluid was difficult to see, but topped up with Dot 4.

The battery SOC is 60.0% could that be because of the weather and because I was running VCDS last night?

[Mechcanico Lee]

If topping the fluid up fixes it bear in mind your brake pads could be getting low or could just be low on fluid for some other reason .

Take car for a good run 30 mins or so and see if state of charge gets any better

I had similar on mine , my auxillary heater kept knocking its self off in a morning , my car has had a new Bosch battery over orginal spec , but in the drop down list bosch batterys was not in there , i was getting the quiecent current stage 1 2 3 codes , so battery regulation stopped the aux heater from working .my S O C was 60 % or around that








See on the coding at the end the 105A im assuming that means 105 amp hour because thats what was on the orginal battery , so i changed that to 115A ....press do it /ok .
It changes the very long code slightly by 1 or 2 figures

The state of charge then went up to 90 % after a 10 min drive around it went up to 100 % , my aux heater as worked a treat since

[Johnmed]

Very helpful and logical Lee.

Thanks.

[Johnmed]

After 50 mins driving the SoC is still 60%. I wonder if this would explain why the D3 has been unable to jump start other vehicles...

[Mechcanico Lee]

Yep ,sounds feasable

[paulrstaylor]

Originally Posted by Johnmed

After 50 mins driving the SoC is still 60%. I wonder if this would explain why the D3 has been unable to jump start other vehicles...

Symptom or cause?

[Johnmed]

Originally Posted by paulrstaylor

Symptom or cause?

The same error code for the battery regulation module was there before I bought the car mate. So I'm guessing it's not because I tried to jump start two cars.

[Mechcanico Lee]

Yes good point Paul with regards to Johnmeds car , with mine (your old un ) battery was brand new and was only getting the 60% SOC .

There was nothing wrong with orginal battery by the way........ just upgraded for the aux heater job .

Power upgraded and dpfs gutted now on the old girl ........ goes like the frekkin wind 42 mpg steady 70 mph ish now

[JulianHicks]

Originally Posted by Mechcanico Lee

See on the coding at the end the 105A im assuming that means 105 amp hour because thats what was on the orginal battery

1. Easy to see why you thought this Lee but actually the 105 A is the last two parts of the part number. The original Audi battery just happened to have a part code that matched its 'Amp Hour' value.

VAG parts are xxx yyy zzz nn = vehicle subsystem part version

2. The Battery Meter % and its associated SOC values in the ECU that you read out with VCDS is one of the mysteries of life. The ECU calculates it and its value is shown in the MMI display but no-one knows what formula is used to determine it. I think Audi gave up on it, which is why it was removed at one of the MMI updates. After problems, I've seen the number 'stuck' at 10% on my car for three days before it magically returns to 100%, so don't trust it.

3. Best bet for working out the battery SOC is to use a volt meter across the battery. - 100% is 12.6V, 75& is 12.4V, 50% is 12.1V, 25% is 11.9V - all approximate values for 'normal' temperatures - Spring in the UK!