Parasitic battery drain

[hcmzah]

Hi all,

Struggling with this battery drain I have. Car is drawing 150mA when off. If I pull out F48/SB48 from the engine bay it drops to around 20mA.
The fuse is for the Vehicle electrical system control module (j519). It seems like this controls a lot of things.

I've done a scan with VCDS and I do have a code for the passenger rear door control module - defective. However, I've disconnected this and the draw is still there. Also tested fuses for this.

Does anyone know what F48 controls? Or any advice? Thank you

2007 BWA, Manual

[hcmzah]

Any ideas anyone? 

[OllieVRS]

I'm in the same boat trying to pin point a battery drain issue, I've been using this for finding out what each fuse does, very handy https://www.startmycar.com/us/skoda/octavia/info/fusebox/2007#anchorfusebox2

[mjmallia]

Have you been checking the car after it has rested for a couple of hours (bonnet popped and switch tricked into being closed, doors closed and car locked), as various modules go into deep sleep at different stages.

[hcmzah]

I found that the J519 aka F48 should control the following (and probably more, which I don't know):
Electrical load management
 Parking light
 Dip beam
 Side lights
 Turn signal indicators (not in exterior mirrors)
 Main beam
 Additional main beam
 Fog lights
 Footwell lights
 Dimmers, instrument lighting
 Hazard warning light system warning lamp
 Relay for headlight washer system
 Fuel pump presupply
 Horn
 Dual washer pump
 Interior lighting
 Rain and light sensor power supply

- I'm going to try code out the rain sensor with VCDS and see if that drops the mA. If not I'll try unplugging it too

I'm in the same boat trying to pin point a battery drain issue, I've been using this for finding out what each fuse does, very handy https://www.startmycar.com/us/skoda/octavia/info/fusebox/2007#anchorfusebox2

Thanks, do you know which fuse is causing trouble for you?

Have you been checking the car after it has rested for a couple of hours (bonnet popped and switch tricked into being closed, doors closed and car locked), as various modules go into deep sleep at different stages.

Yeah I've latched everything and the first time around I left it for 2 hours and it settled to 150mA. From then on I just waited around 25m for it to hit 150mA.

[mjmallia]

The rain sensor saved me a lot of current draw.  Mine had the rain monitoring option on for windows, so it was always checking to see if it was raining and had access to the module to close the windows even when locked.

[OllieVRS]

My fuse giving trouble is the central convenience module fuse, yellow 20amp on the bottom right. Draws 0.1A after all other modules go to sleep, so I assume it's my issue. The car can't be locked or unlocked without the fuse in though, so not one I can take out and forget about.

I'm not sure how to diagnose mine further.

Any luck with yours? I'd be checking all the internal lights are definitely off with the car off, including glovebox and boot. Leave your phone inside recording a video to check.

[OllieVRS]

Unplugged all the passenger door connectors as I had a door light fault code, wasn't that, so I unplugged the next thing causing a fault code, alarm siren. Turns out it was that  now down to 0.02A after about 5-10min after locking

[hcmzah]

The rain sensor saved me a lot of current draw.  Mine had the rain monitoring option on for windows, so it was always checking to see if it was raining and had access to the module to close the windows even when locked.

I had a look at my long coding in VCDS for central electronics and central convenience but it seems the monitoring is set to inactive already (I don't have a sunroof)

Unplugged all the passenger door connectors as I had a door light fault code, wasn't that, so I unplugged the next thing causing a fault code, alarm siren. Turns out it was that  now down to 0.02A after about 5-10min after locking

Nice one! I've read that's one of the most common problems. My alarm seems all good (goes off when it needs to).

I've checked all interior lighting and nothing is staying on, so I'm still puzzled 

[OllieVRS]

You've checked all the interior fuses too?

Unfortunately I don't have any other suggestions, bar an unorthodox one, ask ChatGPT. Tell it the car model (MK5 Golf), tell it what fuse it is and what you've tested already. This is how I decided to check the door connectors and then the siren, following my AI overlord's commands