Replacing battery in Audi A4 (B6)

[OddyRohit]

I did not find clear information on battery replacement for Audi A4 (B6). The following is a step by step guide for the same. My OEM 6 cell battery (MOLL DE MLA) developed a defective cell in the midwest winter. Strangely all internal lights were perfectly bright. However, when I cranked the ignition it would make a rattling sound but never crank up. This would immediately be followed by malfunction indicator lamp turning on, an image of the battery beaming in red color and a beep sound indicating battery malfunction. To verify that battery was the problem I successfully jump started the Audi using my other car. I zeroed in on Werker SLI48-LI from battriesplus.com. It had near perfect dimensions as the OEM battery. Tools - ----- 6mm ball end Hex key Allen wrench, cutting plier, variable wrench or spanner, screw driver. I wanted to get my old battery tested before trashing it. Taking it out turned out to be a nightmare! The show stopper was the harness that clamps the battery down to the chasis. After a trial and error with many tools I zeroed in on a 6 mm ball end Hex Allen Wrench (I got this at a local hardware store). None of the tools I got from Walmart were able to reach down! I had to unscrew the nut by clamping a cutting plier on top of the hex wrench and turning it anti clockwise. You do get 8" or extended length versions of these wrenches which is a little more convenient than the regular 6mm. Removal of the old battery is the 1st hurdle if you haven't done it before. I haven't taken snaps of the removal, but it is essentially reversing the installation process (start reversing from step# 10 below). The following is an illustration of the new battery installation. 1) Place the battery into the slot and yank it sideways so that it fits into the slot. 2) Optionally replace the pollen filter. Unclip the black cover and pull out to expose the white pollen filter. 3) Align the restraining clamp into place and screw the nut using the 6 mm hex key wrench. 4) Push the battery overflow hose into the socket towards the + terminal of the battery. 5) The +ve terminal connector is restrained to the chasis with a plastic button clamp. Push the clamp wedges into the groove in the chasis so that it snaps in place 6) Screw the +ve connector 1st, and lastly the -ve connector 7) Attach the black styrofoam cover by pressing the front along the groove in the chasis and pushing it in towards the wind shield. 8) Wedge the clamp upwards using the screw driver and push the styrofoam cover under the clamp 9) Push the plastic battery cover in the opposite direction of the indicated arrow to lock it in place. 10) Press the rubber seal that runs along the width of the hood. Admire the beauty under the hood - Rohit Gadagkar

[AudiJ4]

Hi Rohit,
I have a B6 A4 1.8T as the same as you showed in the picture. However, I don't have the black styrofoam cover under my hood. So after I washed my car the battery is sitting around soap!! I went to the dealer but they told me there is no such part for my car. Can you get the part number of ther the black styrofoam cover from your Audi? Thank you so much!!

[dhowland]

Great step-by-step write up! I've got a B6 A4 3.0V6 and all the information here was dead on for me as well.

[MG1971]

I followed your instructions. They worked great to swap out the battery on my 2007 A4. Like you said, the harness bolt was the tricky part. But I was able to buy a 6MM allen key with a round end bolt as part of a set at my local hardware store. Using pliers to hold it in place, I got the battery off in under 10 mins total time.

Thanks again for posting, especially the pictures.

[ryaner]

Signed up just to say thank you for the guide. Exactly the same steps on my B7, just that the battery screw was much more difficult to get to due some extra rubber on the firewall.

Still whole job done fore less than half of what Audi wanted for just the battery.