When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hi everyone. I just wanted to post this here in case anyone runs into the same issues i've been having. While I replaced my battery with a new OEM Mercedes one, I was still getting the "Keep engine running" message with the battery icon after leaving my car in the drive way for a few hours or even a day or two. I removed my Alternator and found that the bottom brush was almost shot, and the top one not even touching the alternator. I also had a hole in the regulator cap for some reason.
Once I saw the brushes I ordered a new regulator on eBay (https://www.ebay.com/itm/223004344315). I was skeptical of buying it because it didn't say what AMP's the regulator is and what the voltage of the regulator is. My E300 4Matic alternator (A0009066906) is 250 Amps and 14V. However, after doing some digging I found that it is a 14.3V regulator and it should work by looking at this websites description (https://www.maniacelectricmotors.com/599288.html). That website also references the part numbers on the back of my alternators back plate which is CG25S025. So i'm hoping it works.
I have a few more things to button up and replace in the engine, but when I turn the car on and test I'll update the thread if it worked or not. This could save folks a few hundred/thousand dollars as MB quoted me $1,800 just for the alternator and core charge.
Last edited by Billyismyname; Mar 25, 2024 at 10:21 PM.
Wow, parts like alternators/starters etc are not cheap on these cars. Good find though, hopefully it'll work.
I will update the thread if it does or doesn't I figured spending 65$ on a part that wears out is a lot cheaper than an entire alternator, and will save people money.
--1-- You're doing some real good work for your engine. In case you should keep having the same problem...
- do find the way to set your dashboard to display battery sensor: Amps+ Volts. This will be interesting to understand these live numbers.
--2-- Also consider upgrading your Main chassis GND strap that could be oxidized prematurely to create marginal voltage connection.
--3-- These chassis ALT output voltage is controlled by the ECU via LIN data. AGM Batt can get DRAINED BY DRIVING or WHILE PARKED or BOTH.
--4-- Use a CTEK charger to preserve battery from abnormal discharge by sleepless CAN-B Modules.
Love seeing these threads with the work you are doing. Some of these jobs are not easy and helpful for people that do most of their maintenance work DIY.
--1-- You're doing some real good work for your engine. In case you should keep having the same problem...
- do find the way to set your dashboard to display battery sensor: Amps+ Volts. This will be interesting to understand these live numbers.
--2-- Also consider upgrading your Main chassis GND strap that could be oxidized prematurely to create marginal voltage connection.
--3-- These chassis ALT output voltage is controlled by the ECU via LIN data. AGM Batt can get DRAINED BY DRIVING or WHILE PARKED or BOTH.
--4-- Use a CTEK charger to preserve battery from abnormal discharge by sleepless CAN-B Modules.
let's see what test Voltage/Amps show.
I haven't seen anything oxidized yet. I cleaned off all the terminal cables and the alternator cable and pins. Not that they were dirty or anything, the engine bay has been mostly clean and water free since owning it. I'll update as soon as I do the swap and confirm if it was the regulator its self, as the upper regular brush was barely touching the alternator spindle.
Love seeing these threads with the work you are doing. Some of these jobs are not easy and helpful for people that do most of their maintenance work DIY.
Thanks my friend. I enjoy doing the work and giving the info/advise to others. If I can save money, I love helping others do the same!
Did not work. I re-assembled the entire engine today and started the car up for the first time in about 5 weeks. Got an instant check engine light and when I read the code it said communication to the alternator is not present. I went into the DYNAMIC mode on the cars screen and saw the battery voltage was 12V flat and did not go up or down at all even when revving the engine.
I put back the old regulator and the voltage was higher, but still didn't work correct as my brushes are almost worn out completely. But that just tells me the new regulator did not work. So we W213 folks are SOL when it comes to cheaply servicing/fixing our alternators. Looks like we'll have to dish out $1,074.08 for a "new" refurbished alternator from Mercedes
That's disappointing. That's a lot of money for a refurbished alternator. If I understand it right, the M274/M264 alternator also functions as the starter motor, is that correct?
Valeo remanufactured alternator is retailing at USD592.73 (excl euro import shipping) here. I wish it was easier to import these to Oz.
Did not work. I re-assembled the entire engine today and started the car up for the first time in about 5 weeks. Got an instant check engine light and when I read the code it said communication to the alternator is not present. I went into the DYNAMIC mode on the cars screen and saw the battery voltage was 12V flat and did not go up or down at all even when revving the engine.
I put back the old regulator and the voltage was higher, but still didn't work correct as my brushes are almost worn out completely. But that just tells me the new regulator did not work.
So we W213 folks are SOL when it comes to cheaply servicing/fixing our alternators.
Looks like we'll have to dish out $1,074.08 for a "new" refurbished alternator from Mercedes
I think you skip over too fast to what I think is a wrong conclusion.
A refurb'ed ALT is unlikely to help this.
That's disappointing. That's a lot of money for a refurbished alternator. If I understand it right, the M274/M264 alternator also functions as the starter motor, is that correct?
Valeo remanufactured alternator is retailing at USD592.73 (excl euro import shipping) here. I wish it was easier to import these to Oz.
That alternator unfortunately does not fit the M274 E300 250 AMP / 14 Volt replacement. That website doesn't even sell the alternator needed for the M274 Gasoline model
> SHORTCUT WORKAROUND:
Try to UNPLUG the LIN control ALT connector.
This will restore normal voltage.
It's the regulator brushes that have worn out. My regulator that came with the car/brand new is down to it's last few mm of length. It's not making contact with the spindle of the alternator, therefore not producing enough voltage to charge the battery. The regulator I tried to use was I believe not 14V. It more than likely 12V only.
Only thing that can fix this issue is to get the correct regulator or a new/refurbished alternator. I did however find another Valeo OEM regulator that is 250AMP/14 Volt on eBay so I will be purchasing that and testing it out to see if it works.
Did not work. I re-assembled the entire engine today and started the car up for the first time in about 5 weeks. Got an instant check engine light and when I read the code it said communication to the alternator is not present. I went into the DYNAMIC mode on the cars screen and saw the battery voltage was 12V flat and did not go up or down at all even when revving the engine.
I put back the old regulator and the voltage was higher, but still didn't work correct as my brushes are almost worn out completely. But that just tells me the new regulator did not work. So we W213 folks are SOL when it comes to cheaply servicing/fixing our alternators. Looks like we'll have to dish out $1,074.08 for a "new" refurbished alternator from Mercedes
So MB alternators are like HP printer cartridges? They contain ID chips, and if the alternator isn't "genuine MB" it won't function?
I hope this 3rd regulator does bring you full relief. In the eventuality it doesn't,
know that the voltage regulation is not done by ALT controller.
I am not saying this to purely waste my time but to let ppl know this is nothing new.
I'm not sure what you're saying. But the voltage regulator is a common part that fails after the brushes wear out. All you have to do is find the right specification of regulator and it'll work. The one I tried was 250 AMPs but only 12V. I need 250 AMPs and a 14V regulator.
If you look at the first post I made with pictures you can tell the brushes on the old regulator are worn out to the point they are barely touching the center shaft that they rotate/touch (the red circle I drew in the picture would be the center shaft. The brushes are the silver piece on the left inside the plastic part of the regulator.
So MB alternators are like HP printer cartridges? They contain ID chips, and if the alternator isn't "genuine MB" it won't function?
There is no genuine MB alternators. There is Bosch and Valeo alternators that Mercedes use. The regulator does not have an "ID Chip". The only thing that needs to match are the specifications such as Amperage and Voltage of the regulator and the actual alternator. In our case (well my mercedes model W213 E300) i would need a Valeo 250 AMP and 14 Volt regulator for it to work.
There is no genuine MB alternators. There is Bosch and Valeo alternators that Mercedes use. The regulator does not have an "ID Chip". The only thing that needs to match are the specifications such as Amperage and Voltage of the regulator and the actual alternator. In our case (well my mercedes model W213 E300) i would need a Valeo 250 AMP and 14 Volt regulator for it to work.
How is it that you were provided the wrong alternator -- 12V instead of 14V?
Thanks for clarifying. You can buy a new Valeo unit at https://www.autohausaz.com/pn/VL-0009066906 for $670 (a new alternator not rebuilt). If your brushes were shot, the bearings are probably not far behind.
Thanks for clarifying. You can buy a new Valeo unit at https://www.autohausaz.com/pn/VL-0009066906 for $670 (a new alternator not rebuilt). If your brushes were shot, the bearings are probably not far behind.
I looked at the bearings and they're fine from what I can see. These alternators can last up to 200,000-500,000 miles with no issues other than the brushes wearing out. That's why i was looking to replace only the regulator because spending $60 is a lot cheaper than $670
But good to know that one is being sold for so cheap compared to the MB/Valeo alternators for $1200.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
I figured spending 65$ on a part that wears out is a lot cheaper than an entire alternator, and will save people money.
