New Battery for S4 to fix Brake warning Fault.

Inertiauk

Inertiauk

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I was told on here that the random Brake Warning and dash beeps I have been getting on start and occasionally when driving 'spirited' are just a sign that my battery is getting tired.

I had my battery tested and apparently it has 70% of its life left. I'm planning to change it anyway, hopefully he was wrong because if it is a brake fault it could get expensive..

I can get the battery from a place local to me (might get it cheaper cash on collection).

The correct battery is this one :
Audi A4 S4 Quattro 4 Year Guarantee Bosch Battery | eBay the Bosch S4013

Alternatively for not much more I can get an RS4 B7 battery which looks the same (and surely fits and connects the same) but with much bigger spec:
Audi RS4 4.2 B7 (2006-2010) 09/06-01/08 Bosch Battery S5015 | eBay the Bosch S5015

Would it be worth getting the later battery at all ? in terms of longevity and performance ?
Would it cause any problems (such as not enough charge from the alternator) ?

Thanks.
 
The original battery I'd say is pretty powerfull anyway, and the other battery looks to be about 60mm longer, plenty of cold cranking amps is what you need during the winter, given its 15Ah bigger the alternator will have to work harder / longer to charge it if it gets low.
If the original battery has been ok and never been a problem I'd be half tempted to stick with that size, just a good one such as the Bosch you've found.
I ended up staying with the original size battery on my TDI and it still cranks like hell after 5 years....
 
To be fair, I've only owned the car around 3 weeks but the brake warning light is a concern,

Im guessing the battery that's in it is original, so 8 years old and it still starts ok, just gives this warning.

imwill stick with a new original spec battery then.

Thanks.
 
picture.php



I'd stick with what's meant to be in there personally. A brand new good one will do the job perfectly.
 
That's the warning I've got ! In all fairness the pads seem ok (ish) sometimes the red battery ignition light stops on for a few seconds !
I think I've just answered my own question lol !
 
Any other lights?
Mine has this light on. But it's down to the pad wear indicator connection being poop.
 
Its nothing to do with the battery IMO.

A weak battery can sometimes cause ABS faults ON STARTUP, as the voltage drop messes with the ABS ECU, it certainly wouldnt cause any issues once driving, as the alternator supplies all the power once the car is running.
 
aragorn said:
Its nothing to do with the battery IMO.

A weak battery can sometimes cause ABS faults ON STARTUP, as the voltage drop messes with the ABS ECU, it certainly wouldnt cause any issues once driving, as the alternator supplies all the power once the car is running.
Click to expand...

This.

I suggest that the OP starts with the basics, brake fluid level and wiring connectors, then the brake pads and sensors.
 
thats the pad wear light. are the wear sensors ok? take the wheels off and check. get your multimeter out......
 
Mine is the Brake warning light in red not the brake pad warning light.

Like this on my DIS :
Brake%20warning%20light.jpg


It happens mostly on around 3/5 startups, whilst cranking it comes on and goes off after a few seconds. Its rare for it to do it on a cold startup, usually when the car has been parked for an hour or less then restarted.

It also happens very occasionally (around 3 times in the past 3-4 weeks) when driving hard, on a gear change usually 1st to 2nd, it might be if traction control peeps in. I don't think its ever done it like this with traction control turned off.

Annoyingly it never logs a fault so no clues there.

Due to the majority of the issue occurring when starting the car I am going to replace the battery. I can get one for just under £90 local and DIY really easy.

I have checked fluid levels and wiring to fluid bottle, all looks fine.
 
replace the whole reservoir its alot cheaper than a battery and a more logical place to start.
 
murran said:
replace the whole reservoir its alot cheaper than a battery and a more logical place to start.
Click to expand...

mine has the same problem, replaced reservoir sensor and it didnt fix it! mine needs a new battery.
 
the whole reservoir or just the bit that slots in the side of it?

see if a battery fixes it then.
 
If you need a new battery then get one but it won't cure that issue I don't think. If the light comes on when the engine is running then it can't possibly be the battery as mentioned.

It certainly sounds like a brake fluid issue.
 
I just bought a new battery £89 genuine brand new, cant go wrong at that price. I am going to fit it tonight then will probably be looking to replace the reservoir as recommended, I bet its a messy job though, how to drain it safely before removal ? will I need to have the system bled ? is there risk to master cylinder if done wrong ?

I wont be doing it but I myself but still want to fully understand it before I take the plunge.
 
audi upgrades
Inertiauk said:
does yours come on on gear change when driving hard ?.

I'm putting a battery in tonight, will report back.
Click to expand...

No! yours sounds more like a brake problem. Mine has had all new discs and pads recently anyway and a new sensor on brake fluid.

Mine only happens on start up after the car has been left for a while which is why the battery could be at fault.

Cheers
 
reservior is pretty easy to change.
-firstly make sure both your plenum drains are clear.
-get a big watering can full of hot water. and an old bath towel you dont want. (your guna spill lots of fluid everywhere and its the best thing to wash brake fluid off)
-on the right of the res. there is a feed pipe to the clutch master cyl. undo the clip on it but dont remove the pipe just yet.
-undo the sensor plug.
-under the reservoir going from right to left there is a 30torx headed bolt undo this and take it out. (dont drop the bolt into the plenum chamber.)
-fold up your towel a couple of times and put it bang next to where your working
-pull the reservoir out of the rubber seals it locates on, on the master cyl (it can have a good grip in the seals and needs a good pull). pull the clutch feed pipe off. break fluid will go everywhere, but get it on to your towel quicky and take both away from the car.
-dont touch the brake pedal with the reservoir off.... check the rubber seals are ok.
-grab your new reservoir (remove any blanking covers) and shuv it on the rubbers and push the clutch feed pipe on.
-grab your watering can and liberally pour your hot water over everywhere that might have got brake fluid on. give it a good wash off!
-reinstall the bolt under the reservoir (dont drop the bolt), put a jubilee on the clutch pipe and refill with fluid.

job done and no need to bleed anything.
 
the "BRAKE" warning when you're cold starting is for a battery issue (surge of ampage in cables near to the sensors).... I'm pretty sure that the warning that you have* is for pads, nowt to do with the battery.... *http://forums.audiworld.com/picture.php?albumid=31455&pictureid=61649 I've had both issues over the last few years: the new battery sorted the cold-starting issue, the pads wear indicator (as you've said you have) was abotu 6 weeks after my pads, discs and hoses were repalced, and were fixed by repairing some of the wiring (apparently some of the wiring had degraded due to a combination of age and having been moved when everything was replaced in April, all fixed for free, I wasn't gonna argue). Careful with the larger battery - I went larger and mine was a nightmare to fit!
 
lostbok said:
the "BRAKE" warning when you're cold starting is for a battery issue (surge of ampage in cables near to the sensors).... I'm pretty sure that the warning that you have* is for pads, nowt to do with the battery.... *http://forums.audiworld.com/picture.php?albumid=31455&pictureid=61649 I've had both issues over the last few years: the new battery sorted the cold-starting issue, the pads wear indicator (as you've said you have) was abotu 6 weeks after my pads, discs and hoses were repalced, and were fixed by repairing some of the wiring (apparently some of the wiring had degraded due to a combination of age and having been moved when everything was replaced in April, all fixed for free, I wasn't gonna argue). Careful with the larger battery - I went larger and mine was a nightmare to fit!
Click to expand...

I have done the battery and it has made no difference.

I don't have the Pad wear indicator that is someone else who posted on my thread I have a brake warning indicator,

I am Going to do the Brake fluid reservoir as advised by murran.

Will report back when done.

Thanks.
 
Isnt that the handbrake light? May be worth checking the handbrake applied sensor.
 
audi upgrades
hi, mine only comes on on some start ups. Changed the battery and made no difference! waste of £70!

At a loss as to what it is now, all brakes checked and fine, and had brake fluid sensor replaced!
any ideas??
 
like i said, was it just the sensor or the full reservoir?
 
sounds promising, did you do it or did you get your garage on it?
 
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