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I had an engine compartment SAM that had corrosion like that. I couldn't see how it would have gotten wet but it looked like something that was salvaged from the Titanic.
To anybody out there still reading, I have fixed my “Red Battery Light” issue. Without going in too deep. I came to find that there was a battery drain, but prior to that my assumption was that the rear battery was faulty and/or my alternator as well. After much research I came to find out that many of the issues I stated above (gas gauge faulty, alarm weak, seats ventilating out of nowhere, lighting issues...) came from a Rear SAM malfunction. After taking it out I saw corrosion on the pins. Opened the board and cleaned it.( It was horrible and will post pictures) put it all together hoping it wasn’t gonna work. It looked beyond repair. But thank God it did! All the issues were resolved as far as SAM. Meanwhile I did that... I took both batteries and charged them fully. Voila the Red Battery Message was gone!!! After driving a couple of minutes I noticed on my icarsoft that the batteries were not being charged and the message came back again. I am replacing the alternator as I speak and all issues should be resolved. I wanna thank all here for starting this wild rabbit hole chase that led me to fix many problems with a lot of DIY!
If I was you, I would trash this Sam
It is not reasonable to trust this board anymore. you might get in BIG trouble taking the risk and try to save a few $
There will always be a bucksaver telling you the opposite. risk is high
A friend (?) of mine is a brilliant electrical engineer who holds four U.S. patents that I know of. I think he'd say there's no reason not to keep the module, but he'd caution to look out for future corrosion and possible sources of it. I'd ask him for confirmation, but as long as Donald Trump is POTUS I don't think he'll reply to me. (Yup. He's one of THOSE.)
OMG! That SAM is one nasty-looking board! Did your SL take a swim at some point?
Thank you much for documenting this.
I was very curious to know where the SL resided before my ownership and I came to find out before Nevada the car resided in Oregon for a couple of years so perhaps it took a swim in that point LOL
I had an engine compartment SAM that had corrosion like that. I couldn't see how it would have gotten wet but it looked like something that was salvaged from the Titanic.
Right. Very strange, in this case it’s a lot of corrosion for a compartment underneath another compartment. Maybe left the top down?
If I was you, I would trash this Sam
It is not reasonable to trust this board anymore. you might get in BIG trouble taking the risk and try to save a few $
There will always be a bucksaver telling you the opposite. risk is high
To be fair the pictures do look horrendous and when I saw it at first glance, I gave up on any hopes of reviving it. I am a fool for not taking any pictures of the “after” result (just excited to put it back together) but the board looked great once I cleaned it. It’s pretty much corrosion and gunk free. So far no issues and the car is running great! Thank you for your input
To be fair the pictures do look horrendous and when I saw it at first glance, I gave up on any hopes of reviving it. I am a fool for not taking any pictures of the “after” result (just excited to put it back together) but the board looked great once I cleaned it. It’s pretty much corrosion and gunk free. So far no issues and the car is running great! Thank you for your input
the white stuff is less a issue
the brown stuff is
I need some help please!
I know this seems to be a common problem but it's difficult to find a succinct thread with all the answers!
My 2003 SL350 with 54K miles has just exhibited it's latest "feature" - the 'red battery - visit workshop' light shows all the time.
Some background... the (original I think) consumer battery was taking longer and longer to get up to charge. I had been using a CTEK charger on it permanently, but it would be taking 15+ minutes of driving to clear the 'electrical consumers offline' message. Then one day the 'red battery - visit workshop' light came on and stayed. I thought this was indicating that, yes, the consumer batery was indeed knackered and need replacing.
I replaced the consumer battery, keeping the electrical system alive by using the OBD2 port. All went fine - but still the red light.
I looked online at all the different forums and saw that there could be a lot of reasons for that red light... :-)
One suggestion was that the light came on because the consumer battery was so poor and that it could be reset via the OBD2 port. Is that correct?
I tried disconnecting and re-connecting the batteries. As it didn't solve the problem when I did it consumer battery first, I tried the other way round and that didn't solve it either.
Next up check the voltages with engine off and running. Starter battery - 12.52V and 14.53V. Consumer battery - 12.56V and 14.19V. I assume this means the alternator is working OK....?
I've seen lots about a K57 relay and BCM that may need to be replaced? What do these components do? And would my car still run if they are kaput? As the car starts, runs and drives fine, what is the problem with me running with the red light warning? What's going to fail?
A long post and lots of questions, I know - but any answers/advice gratefully received.
Ideally, I want to avoid an MB dealer..... LOL
ps the other "features" my R230 has exhibited - so far - include the leaking boot seal (an easy enough fix); the random security alarm horn sounding off (due to PCB damage cause by the leaking rechargeable batteries - replacement siren required); and the "stuck in Park" syndrome (a nasty one and a lot trickier and more daunting - but fixed for the cost of a £40 aluminium part).
pps What other "features" can I expect down the line from MB....? :-)
On the battery issue, I went through the same. First a series of Electronic consumer offline errors and eventually the red Visit workshop error. I tried anything suggested in this forum. Unplugged batteries. Replaced consumer battery. Relays & fuses. Nothing worked for me. Some people say just replace the consumer battery and the car picks it up and removes the error after driving some miles. Nope. Not in my case. Bottom line, made a trip to the sweet dealership. They asked for $200 to remove the error. Knowing that the error could possibly come back on any moment, the answer was nope no dealership. Ended up buying a knock off Star diagnosis and was able to remove the error. It's been over a year now and no red error so far. Haven't been driving my car recently due to the pandemic. The Electronic consumer offline came back on again but that's just so expected.
On the battery issue, I went through the same. First a series of Electronic consumer offline errors and eventually the red Visit workshop error. I tried anything suggested in this forum. Unplugged batteries. Replaced consumer battery. Relays & fuses. Nothing worked for me. Some people say just replace the consumer battery and the car picks it up and removes the error after driving some miles. Nope. Not in my case. Bottom line, made a trip to the sweet dealership. They asked for $200 to remove the error. Knowing that the error could possibly come back on any moment, the answer was nope no dealership. Ended up buying a knock off Star diagnosis and was able to remove the error. It's been over a year now and no red error so far. Haven't been driving my car recently due to the pandemic. The Electronic consumer offline came back on again but that's just so expected.
One suggestion was that the light came on because the consumer battery was so poor and that it could be reset via the OBD2 port. Is that correct?
Yes, that is correct, but do know that an OBD-II reader device will not work. You likely want a $135 Foxwell NT510 (reviewed in a sticky) or a clone of Mercedes' proprietary Star Diagnosis costing as little as $200.
Originally Posted by m10279
I've seen lots about a K57 relay and BCM that may need to be replaced? What do these components do? And would my car still run if they are kaput?
The battery control module ("BCM") charges the starter battery and monitors system voltages. Upon inserting the ignition key or switching the ignition on the BCM checks the consumer battery; if it is weak, then the BCM energizes the K57 relay to place the starter battery in parallel with the consumer battery. It also limits the HVAC blower speed, vario roof operation, heated seats, and power to the cigarette lighter.
Since your car is operating fine, there is no harm in you driving it just the way it is with the warning. However, you might want to invest a small sum of money into one of the two diagnostic systems mentioned above and erase the code stored in the BCM to eliminate the message. The diagnostic system may save you future trips to the dealer and quickly pay for itself.
Thanks for the explanation bobterry. Now I understand a bit more about what is going on when I start the car lol.
Also just 'read' the detailed R230 Dual battery on-board electrical system document...
I'm amazed at the complexity of the systems and sensors in this car!
No wonder you need a computerised diagnostic application!
Does it record heart rate and blood pressure too! :-)
2003 SL 500; 2015 ML350 BluTec; 2009 Porsche Carrera S
SL 500 not charging
I'm am going to piggyback on this string because it is chock full of good information and I've performed almost all the tests recommended. Car info - 2003 SL500, 64K miles. About 5 days ago my Red Battery Icon appeared - 1st time ever in 8 months ownership. The only thing I can associate with this event was trying to start the car but releasing the key too soon - I had to go back full "off" and then twist again to restart, which the car did with no problems. On my drive home (less than 5 miles) I noticed the battery icon. Thinking it was nothing much, I put my Foxwell NT520 Pro scanner on and scanned for codes. One code of interest was B1829 "fuse for starter relay circuit component error." Like an idiot, I erased the codes thinking that would cure the problem but the battery message was still on, so I started searching online and landed here. Initially, I was getting full charging of both batteries - the starting battery is 7 months old and the consumer battery passed the load and voltage test (actually had it tested at two different place with two different types of testers). I next dug into the fuses in the passenger floor board - pulled both the 200 Amp and the 100 amp and tested them - full continuity - but I ordered a new 100 amp all the same and it should arrive in the next day or so. Next I tried to check the alternator because I am not get any charge to either battery; I pulled the voltage regulator - looked good and brush length was over 10mm (saw a YouTube video that said more than 7mm was good). I have not tried to test the alternator at the 12 volt output stud with the cable disconnected because I'm sure that's good for the rest of the electronics (ECU, etc.) and because I could find a good test outside of testing at the battery. There does not appear to be any drain n the batteries - just no juice going into them. Finally, I've pulled the K57 relay and K75 relay - the K57 seemed simple to test (always open until energized) but the K75 seems more complicated - closed circuit is the normal operation mode.
I'm considering ordering a new voltage regulator and new K57 relay but I suspect my problem lies in the alternator. Any thoughts would be appreciated.
Cheers
The Red Battery Icon never fails to produce new learning experiences. At first blush, I think that the alternator could be the right place to look, but some parts of the story are not clear. How did you determine that neither battery was getting any charge?
CPDay
2003 SL 500; 2015 ML350 BluTec; 2009 Porsche Carrera S
CDay - I used the live data function on my Foxwell scanner through the "BNS Vehicle power supply control module" function "Body Control Units" menu. Two days ago I could see it was charging the rear battery (Terminal 30) over 13 volts but never seemed to kick over to the front battery. Right now I just started the car - at idle I have 12.0 volts for T 30 and 12.9 for T 30a. Is it possible the BCM is not sending a signal for the alternator to produce volts?
Thanks
The battery control module has no influence on the output of the alternator/voltage regulator.
At idle the voltage on the rear battery terminals (circuit 30) ought to be over 13 volts. Yours appears to be too low, of course, but I wouldn't rely upon any measurement other than one you make yourself with a multimeter.
2003 SL 500; 2015 ML350 BluTec; 2009 Porsche Carrera S
I did some further scanning, this time on the ECU passenger side SAM, looking at the live data under "Voltage" and I got the following with the car at idle: Terminal 30 - 11.8; Terminal 61 - OFF; and Terminal 15 - 11.8. Isn't terminal 61 the power from the alternator? Seems like something has turned off the terminal within the ECU or does it mean the alternator is producing zero? I did pull the voltage regulator and it looked fine but after I reinstalled it, I stop getting any charge to either battery.
Thanks in advance for any assistance.
Terminal 61 is a run status that the voltage regulator sends to the passenger SAM. Since yours shows OFF, this is indicative of a problem with the regulator (likely, in my opinion) or the alternator.
2003 SL 500; 2015 ML350 BluTec; 2009 Porsche Carrera S
Installed the new regulator and the K57 relay for good measure today - problem solved! The battery icon went out on its own and I am getting between 14.1 and 14.3 voltage to both batteries. Terminal 61 is "On" I suspect the the regulator was failing (although I never had any battery charging issues) and when I removed it for inspection that was the final straw. Regardless, this email thread was cruicial for ideas even though I could have started with the regulator and probably ended there. Thanks to all for the creating such an informative site!
Cheers
Socks
2014 E350 Wagon, 2007 S600, 2009 SL550 with ABC removed, 2011 S400 with Hybrid removed
I'm troubleshooting my red battery icon and thinking that designing this dual battery system in R230 went something like this:
- Team leader to engineers: design as unnecessarily complex and as difficult to troubleshoot battery system as you can
- Months later, engineers to the leader: here it is, we did the best we could
- The leader: it is not enough, go back to work and make it even more complex and more unreliable too !
- Engineers: Yes sir!
I don't think any other car on the planet is so unnecessarily over-complicated in this respect, luckily Mercedes killed the idea in the newer cars.
Has anyone thought about what it would take to get rid of that crap and update the car to a single battery system? Thanks!
[QUOTE = George993; 8144851] Я устраняю проблемы с моим красным значком батареи и думаю, что проектирование этой системы с двумя батареями в R230 происходило примерно так:
- Руководитель группы инженерам: дизайн настолько излишне сложен, а устранение неисправностей системы батареи настолько сложно, насколько это возможно.
- Спустя несколько месяцев инженеры лидеру: вот оно, мы сделали все, что могли
- Лидер: этого недостаточно, возвращайся к работе и сделай это еще более сложным и ненадежным!
- Инженеры: Да, сэр!
Я не думаю, что какая-либо другая машина на планете настолько излишне сложна в этом отношении, к счастью, Mercedes убил эту идею в новых автомобилях.
Кто-нибудь задумывался, что нужно сделать, чтобы избавиться от этой хрени и обновить машину до единой аккумуляторной системы? Спасибо! [/ QUOTE]
Great idea! If possible, I will be glad to receive a message about it.
The R231 has a significantly different design, but it's STILL a two battery setup. The main battery (a very large AGM battery) is in the trunk and handles both starting and system loads. The other battery is small (motorcycle size AGM battery) and sits behind the passenger seat. One of its functions is to ensure that you can get in the car with your key fob and shift the trans into Neutral when the main battery is dead.
04-02-2020, 04:15 PM
