Coding new battery

**D ave** · 09-04-2025,01:41 PM

Hi clever people
My car is A3 1.4 tfsi 2009
hopefully someone can help i have just fitted a new battery Bosch S4 E05 640A 60Ah EFB
I have VCDS but cant change the type of battery from wet to EFB very frustrating indeed
any help much appreciated
thx

**Crasher** · 10-04-2025,07:30 PM

What is the VIN?

**D ave** · 10-04-2025,07:59 PM

Hi my VIN is WAUZZZ8P9AA086145

**Crasher** · 10-04-2025,08:32 PM

The coding will be in the CAN BUS controller and isn’t very cooperative.

**D ave** · 10-04-2025,08:50 PM

Agrees not at all cooperative
I discovered that the battery I took out hadn’t been changed on VCDS I’m guessing it was still the original as it was a Varta 68Ah and I suspect it was an AGM type which in my understanding would over charge the one I took out so I don’t want that to happen with the Bosch if that makes sense

**Crasher** · 12-04-2025,02:06 PM

Looking a bit deeper, your car does not have a battery monitoring unit on the battery earth lead so I can’t see it needing coding which is unusual with a stop/start car, then again it is early.

**D ave** · 13-04-2025,01:09 PM

66B2879A-6D94-4C0F-BB0F-EBBE57D90485.jpgHi Crasher it definitely does have battery monitoring on the negative terminal unless thats not ABF7FEBC-43F2-429D-8216-0BCC5B9C3192.jpg ABF7FEBC-43F2-429D-8216-0BCC5B9C3192.jpg

**Crasher** · 13-04-2025,01:34 PM

That means the parts system I am using at home is wrong as a BMU earth strap doesn’t cost cost £35.52, new number 1K0 971 250 CB, the coding is in the CAN BUS and sometimes won’t allow AGM coding so you have to fit the revised BMU, can you see the part number on it?

**Crasher** · 13-04-2025,01:50 PM

Yes, it is wrong. It shows the earth lead twice, in one diagram as the front lead which is wrong and only clarified by the - symbol “ Wiring set for battery -“ it should be original number 1K0 915 181 C and now 1K0 915 181 H which retails at £99.84 which is more like it!

**D ave** · 13-04-2025,06:53 PM

According to the spec sheet of my car it originally was fitted with an AGM battery
J2D Battery 380A 68Ah according to to google thats an AGM battery
so im a bit confused about the need to replace the bmu
ive attached the first page of my spec sheet with the battery showing 1DF67DA8-8E0D-4D7C-8304-FFE12F7BCFCD.jpg