General: Brake Failure after 2 replacement batteries over time

[BenTirony]

Hi folks,

My wife has a 2001 S60T5 that she doesn't drive to the point that we've had 2 batteries replaced in the last couple of years. A month or so after the last battery replacement, I decided to drive it - just to give the battery a charge, but it was so flat that I couldn't even unlock the car with the key fob! Oops! After recharging, we took it for a drive and everything seemed okay.

That must've been a coupla weeks ago and being a sunny winter's day here in Australia (we hope your heatwave in the UK is over soon!!) ... anyway, we decided to take it for a drive again.

This time, the dashboard lit up with "BRAKE FAILURE SAFELY STOP ASAP". Hmm.

After reading some of the threads on this particular problem, I wanted to know what I should do about this, given that the poor car hasn't been driven enough to charge the battery again. I'm wondering if it's because maybe the constantly low voltage states have just tripped up the electronics?

However, it'd be unwise to drive if there really WAS any other issue, so I'd rather recharge the battery or try any other solutions you might suggest on here.

[stuart bowes]

definitely get the battery up to charge first, it's a known cause of issues

also, if you don't have VIDA or another method of clearing faults you can have the battery fully disconnected for an hour or so and that should force everything to reset

when you do reconnect it have key in ignition pos.2 which apparently dampens any potential surge which could in theory damage electronics

I would definitely do that first before worrying about anything more complicated. Fingers crossed it'll just go back to normal working order after that

obviously just to be on the safe test the brakes at low speeds off a main road etc

[Georgeandkira]

What's the odometer reading on this underused '01?

[V70Zig]

You need to check for a parasitic drain and also the charge output from the alternator, they would be my first port of call.

[barrybritcher]

yes dead battery would cause abs module to turn off if very very low

[Simmy]

it sounds like the op needs a battery maintainer permenetly plugged in . under use is a killer for cars .

[Auldgit]

I've had an intermittent problem with battery drain for a long time, two days after a really long trip it can still struggle to start, and when it struggles I get the brake failure message as well. Been unable to trace the drain, 12 month old battery, if disconnected for a couple of days it loses no charge, I can use an Optimate plugged in at home, but it's a b.nuisance when I'm away anywhere without a nearby socket.

I've measured the drain current as 20mA, which is negligible, but something must be kicking in from time to time that really uses power.

[BenTirony]

Thanks Stuart, and apologies for my late reply!
I'll be recharging the battery again tomorrow, I'm expecting it'll take a day or so.

[BenTirony]

The odometer reading was around 245,000 km, that was "regular usage" until about 5 or 6 years ago, when my wife decided to stop driving. Basically, it does less than 1,000 km per year now. Yeah, I know.

[BenTirony]

Originally Posted by Simmy

it sounds like the op needs a battery maintainer permenetly plugged in . under use is a killer for cars .

Thanks for that advice! I've never heard of a battery maintainer but I'll look into it now.

Also, apologies for not replying sooner, I haven't been on here for family reasons, but all okay. But yeah, now it's time to pay attention to this faithful Volvo.