MB Medic Mercedes-Benz Repair Guides, Service, How To DIY
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This article provides instructions on how to replace the battery on the 2000-2006 Mercedes-Benz S-Class W220 and CL-Class C215. Replacing the battery on your S-Class is easy, and you can complete this job in less than 30 minutes. No need to spend over $250 at a repair shop for a new battery when you can replace it yourself. We have even included links where you can find a replacement battery for your S-Class at a much lower price than the dealer or your local auto parts store. Keep in mind that you need to get a Group 94 AGM Battery for your Mercedes-Benz. Absorbent Glass Mat (AGM) batteries are a better option when it comes to batteries for your Mercedes-Benz. The AGM batteries have several advantages over acid batteries, such as being spill-proof, charging faster, and performing better in cold temperatures.
| Years: | 2000, 2001, 2002, 2003, 2004, 2005, 2006 |
| Models: | S430 S350 S500 S600 CL500 CL600 S55 AMG |
| DIY Cost: | $130 to $180 |
| Time: | 30 min |
Tools Required
| Battery Post and Terminal Cleaner |
| Battery Terminal Puller |
| Combination Wrench, 10 mm |
| 3/8-Inch Drive 13mm Deep Socket |
Parts
You will need a new replacement battery. Here are the top 3 battery alternatives for your Mercedes-Benz S-Class / CL-Class. Check the group size against your own car before you order any of them, because they are not all the same size. This guide calls for a Group 94R, and one of the three listed below is sold as a BCI Group 49. Those are not interchangeable: a Group 49 case is about 353 mm long against 315 mm for a 94R, so roughly an inch and a half longer at the same width and height. In a trunk tray with a hold down bracket that difference is the whole job. The reliable answer for your specific car is the group number printed on the battery already in it, so read that before buying. We have provided links to Amazon if you want to check the prices on any of the batteries or read user reviews.
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| Bosch S6588B S6 Flat Plate AGM Battery | ACDelco 49AGM Professional AGM Automotive BCI Group 49 Battery | Exide Edge FP-AGML4/94R Flat Plate AGM Sealed Automotive Battery |
Before you touch a terminal
The order below is not arbitrary, so follow it. Negative off first, and negative back on last. The reason is worth knowing, because it is what keeps you out of trouble: while the negative is disconnected the car body is no longer part of the circuit, so a spanner that slips off the positive post and touches bodywork does nothing. Reconnect the negative first and that same slip becomes a direct short across a battery that can deliver hundreds of amps. A tool bridged across a battery like that heats red hot in seconds, welds itself in place, and can burst the case.
Keep metal away from the positive post. No spanners, sockets, or extensions resting on top of the battery while you work, and take a watch and any rings off your hands first. The cover goes back on the positive terminal when you are done for the same reason.
Eye protection, and no sparks or flames. Lead acid batteries vent hydrogen, which is flammable, and a sealed AGM still vents under fault conditions. This one lives in the trunk rather than out in the open engine bay, so there is less air moving around it.
It is heavier than it looks. A Group 94R AGM is around 50 pounds, and you are lifting it out of a trunk well at arm’s length over the bumper. Get a proper grip with both hands or use the carry handle if it has one, rather than lifting it one handed at an angle.
Instructions on how to replace the battery on your Mercedes-Benz W220 S-Class / C215 CL-Class.
- Turn off the engine and remove the key from the ignition.
- Locate the battery of your Mercedes-Benz S-Class. The battery is located in the trunk, on the right side next to the spare tire.
- Start by disconnecting the negative battery cable. The negative wire is black, and on the battery terminal, you will also notice the symbol (-) or the letters NEG.
- Pull the battery cable away from the terminal. If it doesn’t come off, you may need to twist it. If it doesn’t move at all, you can use a battery terminal puller to remove it.
- Next, disconnect the positive battery terminal.
- Remove the battery clamp. This is what keeps the battery in place and stops the battery from moving around while driving. To remove the battery bracket/clamp, you will need a 13 mm socket and an extension.
- Remove the battery. You will need to grab the battery with both hands to remove it. Car batteries are very heavy. Some batteries even have a handle to make battery installation easy.
- Clean the inside of the clamps using the battery post and clamp cleaning brush tool.
- Install the new battery in place. Connect the positive battery terminal and fasten the 10 mm bolt. Next, connect the negative battery terminal and secure that bolt as well.
- Install the battery bracket or clamp to secure the battery in place.
- Check that the battery terminals are secured and ensure that they do not twist or move. Make sure the battery is secured as well. Try to move the battery back and forth.
Find out why the old one died
A battery that reaches the end of a normal service life has simply worn out, and there is nothing more to do than fit the new one. A battery that died early is telling you something, and fitting another one without finding out means buying a third.
On a W220 the usual culprits are a module that does not go to sleep when the car is locked, so the car draws current all night, or an alternator or voltage regulator that is no longer charging properly. Short trips that never fully recharge the battery will finish one off too. The symptom that points at a drain rather than a worn battery is a car that starts fine when driven daily and is flat after sitting for a few days.
Worth checking before you spend again: whether the car still has faults stored from the low voltage event, since modules log all sorts of nonsense as the voltage falls and some of those will stay stored after the new battery goes in. Reading and clearing them after the swap stops you chasing a fault that was only ever a symptom of a dying battery, and a UCAN PRO scanner will go through the control units rather than engine codes alone. It will not measure a parasitic drain for you though. That takes a meter on the battery cable and some patience while the car goes to sleep.
Resetting BAS / ESP / ETS
Once you disconnect the battery and reconnect it again, you will notice that the BAS / ESP / ETS warning lights are on in your instrument cluster. To clear these warning lights, you will need to start the car and turn the steering wheel from left to right and then right to left two times. The steering wheel needs to be turned all the way in both directions.
Resetting Windows and Sunroof
Disconnecting the battery will erase the memory for the windows. What that means is that when you press the button to move the windows up or down, you will notice that the one-touch open/close no longer works, or that the windows only move up and down a couple of inches at a time. In order to fix that, you need to close the windows all the way, then continue to hold the close button down for another 5 seconds. Repeat the same, but this time lower the window all the way down and continue to hold the button down for another 5 seconds once the window hits the bottom. Follow this procedure with the sunroof as well.
I wanted an OEM battery for my CL500 so I called the lifetime MB roadside assistance number and a technician bought one to my house and offered to install it and dispose of the old one free of charge. I obliged and paid only $185 total, which was equivalent or less than aftermarket brands.