Battery Power Drain

fuse 14 is central locking
check to see if when you remove the ignition key you get a positive click as if not them terminal 86s is not switching off
lube barrel with wd40
also as it got a genuine radio? as if this is not connected properly then this will not switch off 86s
and this will cause you door light not to flash

Sounds like youve already checked but is boot light actually switching off when boot shut? Mine stayed lit which caused a few flat batteries.

Found this thread while searching for the same problem.

I've owned my '02 Leon Cupra for 3 months, and the battery is being drained while off.
It had a new battery about a year ago and it has the original radio fitted.
I've tested the battery drain using a multimeter in circuit and it was drawing 0.6amps with everything visibly off (door was open but latch pushed in to access fuses).
I pulled out fuses starting at the top and when I got to fuses #14 the amps dropped to 0.04 (and that's with the fuse put back in). It's like refitting the fuse has reset something.

I switched the ignition on and off and the draw was back up to 0.6amps, but after about 15min it dropped again to 0.04. I switched the ignition on and off again and the draw dropped to 0.04 straight away.

I've already had a faulty door module, but I fixed that two months ago, which solved the central locking issue.

I think I'll test to see if the battery drains without being connected to the car. My battery goes from 12.3v to 11.8v over night. Alternator is fine.

lights not flashing usually indicates something is showing as open. eg door, bonnet or boot.

Have you checked your glovebox light is actually going out? You can just about see when its very nearly closed the light extinguish

Thanks for your replies.
I left the battery disconnected overnight and it didn't lose any power - kind of obvious, but no harm in trying.
Central locking, alarm and interior lights all seem to be fine - I paid attention to the boot and glove box after you mentioned it, and they do turn off.

I'm going to test the fuses again - the ECU fuse came after #14 and I did pull it out straight after #14. I should've waited a while after putting #14 back in because I'm now wondering if the ECU is the cause. I'll also pull out the fuses in the opposite direction this time, from bottom to #14.

So I tested my battery again for drain while the car's off and tried to narrow the cause down.

Fuse #14 definitely seems to be the problem, but I can't understand why. Everything involved with this fuse visually seems to be working fine, and I have't had any issues. However something on this circuit is occasionally drawing too much power.

Like before, the multimeter is saying that it's pulling about 0.4amps - I then remove #14 fuse and the reading stays the same. I plug the fuse back in and the reading drops to 0.03amps

By turning the ignition on/off the reading settles at 0.4amps, but not every time - sometimes it would drop straight to 0.03. While the draw was 0.4 I tried another test, like opening and closing a door, and once the interior lights went out the reading dropped to 0.03

I can't understand why it's being so temperamental - is it the #14 circuit or is it the ECU? I pull #14 out and the draw doesn't drop until I put it back in - so while the fuse is removed the ECU is still pulling that power.
It's like the ECU is thinking/investigating the circuit because something isn't reporting properly, but then I reset it by taking the fuse out and the ECU is then happy, as if I've turned something off. I've checked interior lights repeatedly and it's not them, so what else draws power that you can't see visually?

Hopefully someone out there has had and solved this issue.

Silly one but is it the right colour/rating fuse for 14?

Find another the same and swap them over, unless you find it was meant to be a different fuse in the first place

Yeah the fuse rating is fine.
I'm going to leave multimeter plugged in for most of the day with the car locked up, then monitor the reading. If it keeps switching between 0.03-0.4 amps then I'll assume that either the ECU is playing up or I have another faulty door module somewhere. Vag-com is usually good at recording faulty door signals, so I'll monitor that too.

I switched on the 'chirp' when I lock the car - cool feature!

check the wiring behind glovebox where it goes up the n/s a pillar
ive had a few looms trapped when they bolt in the dash crossmember

Thanks - I checked behind the glove box and all wires seem fine.

I set the multimeter up today and left it connected for a few hours to monitor the amps. The amperage always dropped to 0.03, and that was after opening/closing doors, locking/unlocking, ignition on/off - a good thing I guess but still doesn't explain why my battery voltage keeps dropping so much overnight.

So the car is fully locked and alarmed and I know it's only drawing 0.03 amps - I've taken a voltage reading tonight (12.11) and I'll check again in the morning. If it drops massively then perhaps I need a new battery.

I've also found out that the drivers side rear door module has started playing up, it's not always responding, but that's a job for the warmer weather.

I have done further testing since but still no luck. Things I've done with no effect:

• Disconnected the rear rear doors at the pillar
• Removed boot light
• Removed fuses 6, 14 & 38 (all central locking, boot light, windows)
• Checked CCM under dash

At the moment I keep taking fuse 14 out when not using the car, and so far the battery doesn't drain. But when the fuse is in, the battery drains by about 0.25v every 12hrs. There was one time when I left fuse 14 out and the battery still drained, but the battery may have not fully charged during it's few minutes run.

I don't know the wiring layout, and I'm not sure if the power goes directly to the CCM or goes via the ECU.
I've seen CCMs on eBay, but I don't want to go down this route because I'm sure the module is fine - it's clean inside, wires seem fine and this part of the system (fuse 14) does seem to be operating normally.

Logically, I see the power going to fuse 14, then CCM, then the various components. So when this fuse is connected, power is being lost somewhere on this circuit - either interior lighting, central locking or electric windows. Fuse 38 also has central locking and electric windows, as well as boot light, so I'll have to see which by elimination.

I can't see power being lost before fuse 14, like through poor grounding, because the fuse is out and the circuit is broken. It's something to do with one of the three areas.

I'm thinking this is something really small and silly like a corroded wire... but where!? I'm thinking a door because that's where it gets damp most, but I've disconnected the rear doors so it's not them. I've stripped and seen all of the front passenger door, which now leaves the boot door and drivers door.

Faulty Battery?

So my battery is still draining when not in use. I have examined all areas of the comfort control unit/CCM, stripped out all lights and even tried a new/used CCM, but the battery still drains.

So today I tried the original test for checking battery drain by checking the amperage at the battery with a meter. At the moment the CCM is still connected and all interior lights are disconnected, but the meter still reads 0.04amps. From what I've read is normal, but it's still draining my battery.

I'm now wondering if my battery is faulty:

• It's only just over a year old, I don't know how many times it's gone flat with the previous owner, but it's been twice for me.
• When I've taken the battery out to trickle charge, it's only ever charged to around 12.6v, but that figure drops even when not connected.
• My journey to work is a 18mile round trip, enough to charge the battery up? The most it's ever charged it self is 12.4v. I check this figure about an hour after turning it off, then about 8hrs later it's dropped by about 0.10v.

It's almost like my battery can no longer hold a full charge and it's discharging by it self, which makes it look like the cars fault. The indicator on the battery shows green, meaning it's ok, but that's only for one cell.

Any advice, because I'm tempted to just by a new battery to see what happens. The battery is a '40Ah/330CCA', which I think is too small for the car - I'm looking to replace it with a '60Ah/540CCA' instead.