348SStb

I bought an exact match AGM battery at Advance Auto Parts today to assist in eliminating variables. It is *not* installed in the car. The car’s pre-existing verified “good” battery is installed in the car.

No- the Deltran Battery Tender Plus plugged into the OBDII socket last night *still* never reached 75% status. It was warm in the morning and still charging.

I currently have the 8amps/auto charger plugged into the engine bay terminals, and I have the Deltran trickle charger plugged into the brand new battery on the bench.

So far neither one is reaching any status increase after a few hours.

crconsulting

I would leave the car alone for now, other than driving it, and focus on getting your brand new battery to read 100% on one of your chargers. If the charger won’t read 100% on the new battery alone, then the chargers can’t read 100% on the car. (just for clarity, we’re talking about the TRUNK AGM battery G1)
That would isolate your problem into two components. Either the battery is to blame or the chargers are to blame right?

It’s also possible the AGM battery is within its predetermined voltage level and won’t accept the charge but -25% is quite a bit more than one would expect to see. Do you have a multimeter where you measure voltage on the battery (on your bench) ? What brand battery is this?

Something is not adding up here….

348SStb

New data. Not complete- will have more tomorrow morning.

Before I get to my data, here are the answers to your two questions: I do not have a multimeter, and the brand and model of the new battery from Advance Auto Parts is DieHard AGM Platinum H8.

As soon as I started the car up tonight with a plan to take it for a few ride cycles — hoping the car would recalibrate itself — the evil “Auxiliary Battery Malfunction” warning message illuminated along with a Check Engine light.

Needless to say, the Eco Start/Stop function worked perfectly during all the drives!

I did 3 drives of about 15-20 mins each with 10-15 minutes of shutdown time in between.

(1) Check Engine light hasn’t gone away
(2) Eco Start/Stop function continues to function perfectly, and so does every other function in the car whether the engine is running or whether the engine is off in Eco Start/Stop mode
(3) Upon starting the car those subsequent times, the “Auxiliary Battery Malfunction” warning message never appeared again. It only appeared that one time upon the first ignition. I’m wondering if it appeared just as a default sequence since the battery was changed by a layman (me) instead of by a qualified mechanic who would use the computer to reset the SAM (or other parameters) upon reinstallation.

My hypothesis: you were right.
Extended hypothesis details:
The bad auxiliary battery was throwing off the balance between the two batteries that the SAM wants to see or maintain. Because of the low level of the auxiliary battery, the SAM wasn’t allowing the main battery to charge over a certain level. That would explain the following:
(i) Why opening and shutting the roof a few times with the engine off the morning of my road trip caused me a battery low enough to not ignite the engine — the battery was at a fairly low level to begin with but high enough to have been starting the engine in the several days prior (car wasn’t plugged in that week)
(ii) Why the battery tender was having trouble reaching the 75% charge tier — it’s fighting a stone wall, as the SAM is pushing back on the battery tender, so to speak

Questions for now:
(A) Will the Check Engine light stay on until someone with a computer clears it?
(B) As long as the Check Engine light is illuminated, does the car think there’s a problem? There’s no malfunction of the auxiliary battery — otherwise the Eco Start/Stop function wouldn’t work at all, correct?
(C) This maybe related to (B) — is the SAM still unhappy?
(D) Does the Mercedes Dealer need to reset/calibrate the SAM / set the balance of the two batteries?
(E) Is there any sequence I may have failed to complete while/ after installing the new auxiliary battery?

Thank you so much for your help!

crconsulting

🙁
Most AGMs will require voltage-limited charger set to float charge of 13.5-13.8V and have a cycle service of 14.4-14.8V so you would think once your charger drops to 90% it should start charging.
https://sunonbattery.com/how-to-charge-an-agm-battery/
Then the small Auxiliary battery G1/13 is probably within specification.
I looked through your previous posts, but never saw you mention this. If this started after you replaced the battery without a backup power source then you will have to read/clear the stored codes.
A good step forward and an indication the batteries are within specification.
The fact that it went away shows the SAM N10 and K114 relay are communicating properly and the SAM adaption procedure appears to be functioning properly. I believe the SAM N10 takes something like 100 cycles or so to adapt.
Yes, most likely. If the CE does by chance go away, codes will still be stored….
Best to have the codes read, recorded and reset, but assuming there were no issues before, your car should return to normal.
Yes they may if the SAM N10 stored data shows any irregularities in XENTRY. There are several settings recorded and stored. The battery charges by temperature when it is in normal driving cycle. It also has a “fast charge” alternator cycle when it deems the battery is discharged after starting or heavy electrical use. The SAM and it’s communication with the other electrical components is an integral part of how the charging system operates.
Typically the proper sequence is to install the main trunk battery G1 then hook up the Auxiliary battery G1/13. Also disconnecting the main battery G1 for more than 15-20 minutes resets several component stored settings. This can sometimes lead to some unintended consequences.
In the end you’re kind of flying blindly without XENTRY (or a competent scanner) for these types of electrical component issues.

Good Luck

crconsulting

In addition to the wiring schematics and overview .pdf's supplied by @jmattioni
Attached is some additional WIS documentation that may help others.

348SStb

First off many thanks to user <crconsulting> and other thread contributors.

I have new data and I think I am near the end here. I summarize as follows.

Current problems:
a. When charging the vehicle, the charging process still does not complete to float status. (Possible suspects: restriction by SAM due to prior charge imbalance, bad SAM, bad other components)
b. Check Engine light remains illuminated despite completely normal operation of all vehicle functions including the Eco Start/Stop function. (Suspect: the action of a layman such as myself installing a new auxiliary battery while not knowing advanced protocols.)

Current circumstances:
1. Pre-existing OEM main battery (installed 3.4 years ago and the original suspect which was verified good using a diagnostic tool) DOES REACH 100% charge and float status in isolation using either the intelligent battery charger or the Deltran Battery Tender Plus.
2. Newly installed auxiliary battery (purchased a few days ago after pre-existing auxiliary battery 6.25 years old was verified bad) DOES REACH 100% charge and float status while installed in the vehicle using the Deltran Battery Tender Plus.
3. Brand new main battery (Die Hard exact fit AGM from Advance Auto Parts) DOES REACH 100% charge and float status in isolation using the intelligent battery charger or the Deltran Battery Tender Plus.
4. Brand new Die Hard main battery while installed in the vehicle WILL NOT CHARGE to satisfaction of either the intelligent battery charger or the Deltran Battery Tender Plus.
5. I have not been able to draw a conclusion on the question of whether charging the main battery from the terminals in the engine compartment also charges the auxiliary battery.

Questions:
i. I suppose I CANNOT AVOID a trip to the Dealer. It seems the Dealer needs to not only clear the Check Engine light but also reset the SAM in order to lift the restriction that the SAM is placing on the charging situation. Agree? (I am aware that <crconsulting> previously stated that the SAM appears to be working properly, but I'm not sure I want to perform around 100 drive cycles before my car will trickle charge normally.)
ii. Since it's impossible to obtain a Dealer appointment within a reasonable amount of time, I called an independent European auto shop who was recommended. Technician said a multitude of sensors need to be reset after battery replacement -- not just the SAM. (Said it takes a couple of hours.) Is this accurate?
iii. Technician in (ii) said he always installs the two batteries together in order to maintain age parity. My main battery is 3.4 years old and still good. I am thinking: if I am going to pay Mercedes anyway to perform their computer work, I may as well install a new battery now so I don't need to pay them to do it again in 2-3 years. Agree?
iv. Technician in (ii) says he doesn't like the Die Hard batteries in general. Hasn't had good luck with them. I replied I like the 3-year warranty as opposed to the 1-year from Mercedes. Any good reason not to use the Die Hard?
v. Fyi -- technician in (ii) is also booked out a few weeks. Welcome to South Florida. Therefore I am going to try to pop in to Mercedes early in the morning one day. How many hours of labor do we think is necessary to perform the necessary operations? I am thinking they could do this in about 40 minutes and not charge me the obligatory several hours of labor if I am able to convince them to be gentle with me.
vi. Will Mercedes scoff at me when they see the Die Hard battery in there? Mercedes Certification expires 09/30/2023; and while I do not take BS crybaby excuses lightly and I have successfully fought against BS dealer excuses, could I expect the variable of a Die Hard battery to be introduced by the Dealer now or down the road? (It's a battery. It's a dumb, physically constructed enclosure that provides power that isn't intelligent. Mercedes' battery ins't any less basic.)
vii. Suppose I say the heck with these matters for now and just drive the car as is. Are we still okay with that?
viii. For my future reference -- what is the procedure to connect backup power to the car during battery replacement? Can I guess here? Supply amperage (8 or 15 amps?) directly to the metal connectors that interface to the main battery itself by attaching the battery charger jaws to those connectors, positive and negative. Is that correct?

I have prepared verbiage for the Dealer which details the story of where I was, where I am now, and where I'd like to be. This is also background information for those looking to benefit from my experience. It is provided below.

<<
Customer states main (starter) battery previously reached 100% charge and float status while charging with trickle charger during vehicle storage. Customer states main battery recently did not accept charge to 100% prompting Customer to review the status of the vehicle’s two batteries. Customer states main battery previously replaced at external Mercedes dealer 03/2019. Customer verified main battery good with diagnostic tool. Customer verified main battery reaches 100% charge in isolation. Factory-installed auxiliary battery with production date code 1916 (week 19 2016) verified bad by Customer using diagnostic tool. Customer installed new Mercedes OEM auxiliary battery. Customer verified new auxiliary battery reaches 100% charge and float status both in isolation and after installation. Main battery when installed still does not accept charge to 100%. Customer test drove vehicle after auxiliary battery installation. Check Engine light illuminated. Customer verified Eco Start/Stop function and all other vehicle functions operate normally during test drive. Customer verified the same after four drive cycles. Customer states SAM is still restricting charge of main battery due to prior charge imbalance between the two vehicle batteries. Customer subsequently installed new main battery in order maintain age parity across the two vehicle batteries. Customer states new main battery accepts charge to 100% in isolation but after installation the pre-existing restriction from SAM continues to restrict charge. Customer is requesting clearing of Check Engine light and resetting of SAM as necessary together with any other necessary operations after battery replacement. Operations completed. Customer also requests technician attach known good battery charger to terminals in engine compartment to verify that vehicle charge now reaches 100% and float status. Operation completed. Vehicle ready for pickup.
>>

348SStb

Update.

I went to the Mercedes Dealer today (Saturday) to beg if they could squeeze me in and quickly reset my vehicle’s SAM. Going on a lengthy trip Monday and I’d prefer to plug the car in without issues.

The Check Engine light actually disappeared upon vehicle ignition when the porter and I drove the car over to the Mercedes technician’s bay. So no Check Engine light variable.

I told the technician the car recently stopped charging to 100% float status which prompted me to investigate health of batteries. I indicated I changed the two batteries and the problem persists after various drive cycles despite the batteries both having been brought to 100% charge in isolation prior to installation. The technician did not seem interested in previous documentation I had with me from an external Mercedes dealer which reads, “reset SAM and charge balance.” Instead, he said there is no reset sequence. He said there is no charge balance issue. He also said the SAM is active when the engine is running, so the SAM wouldn’t be interfering when the car is off and trickle charging.

The technician plugged in the Mercedes Xentry computer and proceeded through his sequences. After a few minutes, he shook his head and said, “There’s nothing to reset.”

I repeated that the previous dead auxiliary battery must have thrown off the charge balance and the car is restricting charge to the main battery. He dismissed that hypothesis and said: “Does the engine start okay? Then I wouldn’t worry about it.”

I said, “What about long-term storage?” He said, “I don’t trust trickle chargers. They are cheap devices that aren’t useful.” “What about my intelligent battery charger,” I asked. “If the car starts fine, I wouldn’t worry about it.”

And that was that.

Not exactly a scientific approach to the problem.

I think this particular technician was NOT well-versed on the battery change procedure on this car. I do not think he was helpful at all beyond the fact that he was willing to stop what he was doing and plug in the Xentry computer. I think he was wrong about everything he said. Does anyone agree with him?

Just my luck to sneak into an unplanned time slot at the Mercedes dealer and be paired with a technician who both didn’t try all that hard and who had a false bias against my ideas the entire time.

Lastly: when I arrived home a short while ago, I plugged in the battery charger. The car still seems to be restricting charge. In a normal situation, within 10 minutes the chargers shows a positive change in status — whether using a trickle charger or a regular battery charger.

What now? Another Mercedes dealer?

crconsulting

I think your best bet here is to compartmentalize your issues. Firstly the check engine light. You need a scanner to read/reset this. Without this, you are dead in the water and are at the mercy of what ever shop you bring this to. I'm assuming the car has very little mileage and we know it worked properly before. Therefore you have to assume the check engine light was triggered because it recorded something outside the normal parameters. The car runs normally therefore we can also assume this CE light can be cleared and never come back. Also as I mentioned above in post # 104 It may actually go away by itself, but codes should be stored (edit: looks like it did from your response post #107)

Being that you have other vehicles you may want a scanner that works and resets codes on some of your other vehicles. There are many posts in these forums about OBDII scanners and I would do some research and see what suits your needs best considering the vehicles you currently own. Errors that trigger a CE light will show up and be able to be cleared on most quality code scanners. Either way, you need a way to read the check engine (CE) and reset it. Without this, you're bringing it to whatever shop/dealership, being at their mercy, and having them deal with both issues.

These modern cars are complex, and as such can be difficult to diagnose. It's completely common nowadays to bring a car with an electrical problem to three different shops/dealers and receive three different diagnosis! Look at it from the techs perspective. Sure you get training, but outside the norm electrical issues can be a bear to track down. There's no flow chart or any amount of training that will solve outside the norm problems. Sometimes, if you get unlucky and get a tech that is inexperienced or incompetent they may even create new issues. This can quickly spiral out of control, with the customer being flooded with misinformation making the problems seem worse than they actually are. It's one of the reasons I have trust issues. We've all read/heard so many example on the internet and honestly I believe it's rampant. If you can't find labor for restaurants, imagine how difficult it is to find a competent experienced tech....

These cars monitor so may functions and like any other "smart" device, they can sometimes have a mind of their own. Think of how many times you have re-booted your phone/ipad or PC? These cars are no different from that standpoint. The difference is if something runs outside it's perceived acceptable parameters, it records the error and calculates if it's necessary to give you a warning message or dash light or store for later diagnostics. Typically most techs will record any codes triggered and reset. Only if the codes/light/warnings come back will it be truly verified as a real issue. Every car I hook up to XENTRY for the first time, typically has a few "false" codes recoded. Once cleared, they don't come back unless there is a real issue.

In post #87 you said
This DEFINITELY reset several stored memory settings. The car needs to go through a relearning cycle and it's quite possible for something to have triggered the CE light.
This probably will need to be reset to go away.

Since you removed BOTH battery's, the vehicle could be trying to measure and adapt to it's new "perceived" operating conditions. ie new battery.
Remember your car is not new anymore and has some parameters already stored, and some it needs to relearn now. Coupled with the fact you're not driving this car too much, could be one of the reasons it's not adapted yet. I would be patient here, and try NOT to obsess too much on the why the charger isn't charging as it was before, but rather whether the the car is operating properly in actual operation.

When charging, if you are charging thru front jumper terminals of the car or OBDII. The front (and rear) SAM's are controlling voltage to your battery. If your battery is 100% charged it's quite possible for the front SAM N10/1, rear SAM N10/2 to not allow the charger to go thru all it's cycles. There are several cycles the charger must go thru in order to reach "float". The Deltran Battery Tender Plus charging cycles are going to be similar to the CTEK charger. This gives you an idea of the charging process for AGM's.

Also, since you have established that the battery/charger combo will charge battery to 100% directly attached to it. You may want to temporarily charge the battery in the trunk directly. Until you get some mileage on it and then reassess....

Since you don't have a multimeter. You may want to consider something like this CTEK battery sense. It can be read from any iphone. All you have to do is stand within bluetooth range of the car.
I use one on my R231 and it works very well. I use it as a guide on just when it's time to trickle charge my battery and its actual condition so I get no surprises. It can also help diagnose problems. You could also put one on the Auxiliary battery G1/13 to monitor it. Since I drive my car a couple times a week I only trickle if I don't plan on driving the car for a month or so.








As stated above: You need a scanner to read/reset this. Without this, you are dead in the water and are at the mercy of what ever shop you bring this to

As stated above: I would be patient here, and try NOT to obsess too much on the why the charger isn't charging as it was before, but rather whether the the car is operating properly or not, in actual operation. Also, since you have established that the battery/charger combo will charge battery to 100% directly attached to it on the bench. You may want to temporarily charge the battery in the trunk directly. Until you get some mileage on it and then reassess....

I would not obsess on this at the moment. If the car drives properly in eco mode chances are it is operating properly. You may also want to attach the CTEK battery sense

For what its worth, when I had a 100% charged battery, my CTEK did eventually cycles to float hooked up under the hood. It took longer than if I charge it from the battery directly.
see @jmattioni #84 post above, it is accurate....

I'm not sure it will take all 100 cycles. The SAM records 100 cycles. (se picture 1, post #91) I'm not sure, nor have I found documentation on EXACTLY how long the process takes. These cars are designed to be driven. The SAM is probably going to need some drive cycles. It's only going to get worse the more electrically "sophisticated" these new cars get.
https://blogs.nvidia.com/blog/2020/0...ined-vehicles/


No!

Theoretically a good idea for the the end user. But in actually application, wasteful and not necessarily practical. Batteries can be monitored with things like that CTEK Power Sense.

I prefer genuine OEM Mercedes batteries. as mentioned in my other post, the AGM battery has a predetermined voltage level where it won’t accept a charge. Doubtful, but there may be some variations that are affecting the SAM and other components.

They may have a flat fee to hook it up to XENTRY (one of the dealerships out here used to be about $250) and clear any codes depending on the dealership. But you're bringing the car in with a "problem" and that requires diagnostics. It will depend on their policy, but typically that's not how it will work.

They may and it shouldn't, but depends on the dealership, service writer, mechanic and your relationship with them.

Get the CTEK Battery Sense or similar product installed and monitor....
Drive, Drive, Drive! Car is not designed to sit...

Mercedes recommends you use a "Memory Saver" and as mentioned above: Typically the proper sequence is to install the main trunk battery G1, THEN hook up the Auxiliary battery G1/13.


Hope this helps.

Good Luck!

348SStb

Crconsulting —

I guess we were typing at the same time!

My post executed just before yours.

Thanks for your excellent response.

crconsulting

crconsulting

This is good read for anyone interested in this subject.
Rather than copying this well written article, I’ll just link to it below. Anyone can join. You just have to register.
It may help:

https://automotivetechinfo.com/2019/...-that-battery/
.

btw, I use the Micro717 to conductance test batteries. They can be found under $200.

dsrsrqmb

Hello,
Just heard about 'programming vehicle' after main battery change ??
My suspicions are high at this - can anyone here verify ?

Reason for question is 1 yr old battery replaced DIY, shop states that battery only showing 700 amps of the 1,000 recommended...
Shop states that vehicle was not programmed after battery change and now alternator is putting out excessive charge and degrading the existing battery ???

Granted my understanding of alternators and batteries is based on 'old school' laws of demand and supply.
Any help is appreciated.

ThatsMyDawg

I changed both batteries and nothing had to be "programmed" afterwards. I talked about it in a post.

Joshua

Awesome post and great detail. Very helpful.

I am struggling to get replacement batteries without having to go the main dealer option in Australia. I wonder if you are able to provide me with the OEM Mercedes Part Numbers for the main and auxiliary battery please. Or at least post me to a reliable source of info. Happy to do my own digging.

My model is a W222 2019 S560
VIN: WDD2220832A516145

I believe the original batteries that came from new are re-badged VARTA ones.
I also have gotten close to local replacement models but need confirmation. They appear to be VARTA Sliver Line AGM.

Thanks

Bitbytr

I just bought a replacement (from O'Reilly above all places for $120) whose specs were better than the twelve year old original I had to replace and it took me less than half an hour to undo everything, remove and replace the battery. It was much easier than I expected.

crconsulting

I’ll post the attached .pdf’s from the WIS on battery R&R here, in an effort to keep the battery info in one thread.
Just to confirm, there is no battery registration on R231. Also note, it says to re-set clock, implying no battery specified/needed to preserve anything critical in the onboard memory.

See attachments.

348SStb

This is great, thank you!

jmattioni

I think the confusion about battery reset is because there are some Mercedes models that need it, but not the R231. Most likely it SHOULD have had a battery reset function. That might have saved us all some headaches trying to figure out what's wrong. It would be nice to consistently get a clear message when a battery is no longer up to par. On the R231 that sometimes happens, but it often doesn't. The problem is that all those computer modules are sensitive to low voltage conditions and can reset unexpectedly if the voltage drops too low. You may then start to get a collection of bogus fault codes.

I just replaced the batteries in my S560 (2018) and it required a battery reset. I was able to do that with my fairly cheap Foxwell scanner. There were several fault codes (including complaints about a camshaft sensor) that went away after the battery replacement.

jmattioni

Another tidbit concerning changing the main battery.

Many newer battery maintainers have a "power supply" mode that can be used to hold memory while replacing the battery. A charger is likely not going to work to hold memory.

The power supply mode is also useful for maintaining voltage while running diagnostics, coding, etc.