Hi all,

I'm hoping your combined wisdom can help with 2 flat batteries I've had in 2 days in my manual 2.0tdi octavia scout 

 

So , he other day I had the RAC out to a flat battery which was 7 months old and when tested had dropped to 8v but showed as taking charge once jump started with the alternator supplying 90amps.

 

I ended up fitting a new battery but within 48hrs this to was down to 9volts so definitely something is draining the battery.

 

As a background in the past 10 days prior to the flat battery my ABS light has been on due to a known fault with the drivers side front ABS sensor which had its connector repaired in january but has reoccurred and is booked in for repair (RAC man confirmed this was a recorded fault code).

 

When the engine is off I can hear a pump running for 5 mins from under the bonnet ( under the black plastic cover on the right side on the engine when looking from front).

 

So any ideas what is causing the flat battery ? ( new battery down to 9v within 2 days)

 

Could a faulty answer sensor or connector cause a drain with the engine off ? (Thinking of a short)

 

Is the overrunning pump possibly a culprit ( it sounds louder than any usual overrunning pump I've hear before on this car).

 

Thanks folks, I really hope you can help .

 

3rdOctavia

 

 

 

 

 

 

I meant the pump noise is on the left of the engine when looking from the front . I also had a sauna warning about component protection being active the day before it wouldn't start. Cheers

*satnav

It sounds like you have a direct short on a component in the car. Just wanted to make sure you haven't added in a dash cam and wired it to permanent live by accident or something daffy like that.

 

We need a scan of your car to help. Can you get someone with VCDS or ODBEleven to perform a scan on your car and post it up here pls.

 

Can you also take a short video of the noise pls?

 

Almost certainly not the ABS sensor/connector, I think.

If you have a multimeter that has dc current ranges, I've done a guide on a method of getting a true reading of the quiescent current of the car when fully off. 

It sounds like you might need to use a high range, amps rather than milliamps.

Quick and dirty parasitic current measurement - Handy Topics & Guides - BRISKODA

 

This needs urgent fixing, obviously, as batteries will be permanently damaged by such deep discharges.

Edited 13 August, 20214 yr by Wino

No, the ABS fault would not cause a flat battery, but a flattening battery can manifest itself as an ABS fault (personal experience with a sticky alternator clutch).

Hi all, and many thanks for the replies so here is a bit of an update.

 

This morning the battery started the car but showed 12.4v and when first started the alternator supplied 12.8v DC then after revving settled at 13.4v DC .... with 0.8mv ac

I don't have access to any diagnostic scanner but when the RAC guy scanned it it showed about 2-3amp of draw for about 4 mins and then dropped to zero. This was after the battery had been jump started but on a cold engine. I checked yesterday and this timing seems to coincide with the noise which I can hear in drivers seat after the engine is off and has  a similar sound to when the cabin blower is running very slow....more of a sound of air/fluid  flowing than anything else.

Under the bonnet the noise had various clicks and switching noises associated with it ... sort of like when the Aircon is adjusting itself with a very quiet sound of something running under the plastic cover directly attached to the left side of the engine when viewed from the front.

In an old audi I remember doing a throttle body reset procedure which made similar clicking noises.

Cheers

 

Well, you might have a short on the blower motor - they can fail....you could have to be unlucky to get a short on one of those.  You are going to have start isolating circuits (carefully) to identify which circuit is pulling a lot of current.  You might also have a compressor failing (which will take a lot of current).  When was the last time the HVAC system was serviced (should be every 3 years).

 

The RAC reading looks about normal.  You can find local people with VCDS for reading info from the car - or you can go and purchase an ODBEleven for diagnostic support.

Another update !

 

I took the car out for a drive and determined there are two noises when stopped with key removed. One Is the very quiet sound of the secondary oil pump I think as I've heard that before .... any idea where this is under the bonnet ?

 

The second and much lower noise changes when the steering g wheel is moved. I noticed this as when parked for a few minutes with he key out the noise changed, resistance was lost slightly in the steering wheel and it seems to slightly turn itself (when the hydraulic pressure released??) And it clicked into steering wheel locked position then went off completely after about 5 mins.

 

So I'm wondering if the abs pump is running on and if that is draining power and keeps waking up through the night? This might tie in with the abs light, power steering light, tyre pressure light and traction control lights all being on... which I thought was due to the drivers side abs sensor.

 

Is there a way to check this by removing a fuse or relay for the ABS .... and is the abs module at the back left if the engine bay where I can hear the noise ?

 

Thanks all,  I really appreciate you help. 🙏

I've just reread this and think it's the power steering pump I'm probably talking about as that is linked to the steering wheel.

 

As you can tell I'm not that good at this car stuff !

You have electromechanic power steering so there is no power steering fluid or pump

 

You should get the car checked for fault codes and perform a parasitic current draw test to confirm what, if anything, is consuming power when it's turned off.

Ideally you need to use vcds or obdeleven etc to see what is going on. If you have any warranty then let Skoda take a look as they can use odis to diagnose any issues.

1 hour ago, langers2k said:

You have electromechanic power steering so there is no power steering fluid or pump

 

You should get the car checked for fault codes and perform a parasitic current draw test to confirm what, if anything, is consuming power when it's turned off.

 

1 hour ago, Ecomatt said:

Ideally you need to use vcds or obdeleven etc to see what is going on. If you have any warranty then let Skoda take a look as they can use odis to diagnose any issues.

 

Thanks guys, I've got it booked in with my local garage in 2 weeks for the abs sensor but also have it booked in with my local VAG indy in 4 weeks time to look at any remaining electrical issue if the local garage can't get to the bottom of it. The Indy chap was happy with that and knew his stuff by the sound of things, he said to keep a log of anything that was odd with the electrics though which might point them in the right direction.

 

The electromechanical power steering sounds interesting as I think that's a step up from my old 2006 mk2 okty . I've had a quick read online and it sounds as if the power steering motor should only be activating when needed but mine  sounds as if it is working continuously for around 5mins after the key is removed. Does this have a permanent live and would a fault stop the canbus from going to sleep too so adding to overnight current  drain?

 

Does the system have a fuse or relay that can be removed to help diagnose, and does it draw a lot of current ?

 

Sorry for all the questions.

 

Cheers

 

 

 

Hi all, just as an update.

I took the car into the garage and they said there wasn't of codes relating to low electrical power probably related to the battery going flat.

They replaced the loom to the front drivers abs sensor and all seemed OK with the battery and when locked everything seems to shut down as expected so they cleared all the fat codes.

I took the car home on Friday, half expecting a dead battery the next morning but its started every time since !!!

So fingers crossed it was the broken ABS loom that was somehow causing the battery to go flat every night somehow (new battery lasted 2 days and dropped to 8v)...

Does that sound plausible??

Cheers

If there was a break or a short in the loom then anything is possible.

I've got it in with my local VAG indy tomorrow who is going do another check to see if there are any new fault codes. He is doing a haldex oil change and filter clean too so it won't be a wasted journey.

Cheers