Coalman

I was getting a "Take to Workshop" malfunction code with a battery in red symbol so I figured it was time to get a new battery. I still had the original battery after 7 years so I figured I better replace before Winter. After installing, I still got the same malfunction code after the first 1 or 2 starts. I then got a malfunction code saying ESP was not working. I then noticed the windows stopped express up mode. On the positive side, the car felt a little stronger, but I am sure that will not last.

The ESP worked fine despite code and I have not ,as yet, had a repeat. Same for the battery malfunction code. I had to resync the window buttons and they seem to work fine. Now if I can only figure out how to keep the performance improvement. Sneaky reset never worked as well for me.

Turbo 6

If I'm not mistaken you have to turn the steering wheel all the way to the left and the right to reset the ESP. I had to do that after disconnecting my battery. Also had to re-sync my windows.

buffyclk500

ya when i took my battery out i had 2 redo my window
but in the e55 i think u have 2 battery just fyi

izzyz28

Turn the wheels lock to lock a few times to reset the steering wheel angle sensor. Also, go ahead and replace the small battery at the front of the car before it goes South as well. Chances are it's junk anyways, and the car won't tell you when it's going bad.

Coalman

Thanks all for responses. MB said nothing about the need to reset ECU. Can I replace the front battery with an aftermarket battery and how difficult is it to replace?

Tom_Boy

you will needto re-sync the sunroof too...

lilg210

What is the syncing that you all are talking about???

izzyz28

The front battery takes 5 minutes. Go to your favorite auto parts store or Wally World and pick up a group 14 or 18 AGM motorcycle battery(can't remember which). It takes 5 minutes to replace and is located under the cabin filter in the right rear corner of the engine compartment.

To re-sync, raise and lower all windows and continue to press each button up or down for a couple of seconds after each window stops moving(so the ECU can see the extra load and set endpoints). Turn the steering wheel lock to lock a few times to make the SWAS and headlights happy. Finally, you will have to keep inching the sunroof all the way open and closed for it to relearn.

Benz-O-Rama

Sounds like you replaced the wrong battery. As izzyz28 mentioned, this is most likely the front battery that needs replacing. There's a great thread in the W211 non-AMG section about this:

https://mbworld.org/forums/e-class-w...ml#post4293262

I just had the same issue this weekend. People mention in the thread that the dealer wants 400.00 to replace this battery. I followed the procedure in the thread, and purchased the Walmart battery for $79.00

Jakpro1

When you disconnect battery, you have to resync ESP. Not sure why, but you need to start the car and turn the steering wheel end to end a few times.

2 each way should be good.

Then resync windows and sunroof. Hold down buttons to bring windows all the way down, then bring them all the way back up.

Sunroof you have to hit the retract button a few times as it will go back a few inches, then stop. When its fully open, hold retract button down for about 3-5 sec. Same way closing.

That's about it.

izzyz28

For what it's worth, I thought my front battery was a-ok. It measured 12.7v when I pulled it out, but as soon as I put a tiny 10A load on it the voltage dropped to 9.xx volts. I'm definitely glad I wasn't unfortunate enough to have to rely on it in an emergency.

Benz-O-Rama

My front (AUX) battery measured in with a whopping 8.5V! It was very easy to determine that this was my culprit. Went to WalMart and purchased the ES14-BS AGM battery, added the acid/electrolytes per the instructions, waited 30 minutes for it all to marinate, threw it on a trickle charge for 2 hours, and installed it.

You before starting your car, you're supposed to put a load on the aux battery by turning on your headlights, rear defrost, seat heaters, etc.... for 2 minutes.

Front battery now measures 12.XV

Coalman

This is helpful, but can someone tell me exactly where the front battery is located and how to remove it. I guess I should disconnect the positive terminal from the back battery. What about resetting accessores other than what I went through when I reset rear battery? Assume I know nothing because I don't. Also, would you recommend the $20 Walmart battery. I feel a little uncomfortable with this one.

izzyz28

The front battery is located under the cabin filter box in the RR corner of the engine bay just behind the windshield washer fill cap. Remove the 1 10mm plastic nut holding the box down and lift the front of the box up to unhinge and remove it. You will now see the battery.

Remove the positive and then the negative 10mm bolts holding the leads to the terminals(You do not have to disconnect the rear battery). Push the leads aside and remove the nut holding the battery hold-down bracket in place, remove the bracket and then the battery. Installation is the reverse of removal, and there shouldn't be anything that needs to be reset or relearned as long as the big trunk battery stays connected.

The replacement battery you buy should be the "AGM" type. It will say so on the box and will probably be the most expensive battery they have, at around $80.

Coalman

Outstanding! Thanks.