I was driving to dinner yesterday and got a "Battery/Alternator Visit Workshop" error on my dash. I thought this issue would be something I could wait until Monday morning to take care of. Unfortunately I was wrong.

The car drove fine at first, but a few hours later the car started to die on me. The ABS, SRS, and other lights lit up on the dash. The radio showed a low battery voltage error and then all electrical power started to turn off. The headlights stopped working and the car was sluggish. I was lucky that this happened right after I exited the freeway. I managed to drive to a safe neighborhood and parked while waiting for a tow truck.

Getting the tow truck to lift the lowered C55 was an issue. I had to call 2 different tow truck guys to attempt the tow. First guy came and right away he told me that my front bumper and rear tail pipes would be damaged from the tow. This guy seemed convinced that there was no safe way to pull the car onto his flatbed. He told me to sign a damage liability waiver, but I declined. I sat there deciding what to do. I didn't want to damage the car, but damn I was stuck and didn't really have any other options.

I decided to take my chances and call a second tow truck company. The second tow truck guy was really helpful. He used 2 blocks of wood to help gain extra clearance onto the flatbed. My girlfriend and I taped up the front lip with semi-thick bathroom towels. The C55 was slowly pulled onto the flatbed with the front bumper hitting the metal flatbed. Luckily the towels cushioned the lip and no scrapes occurred.

I was so relieved there was no damage to the car. The car died at 11pm and it was now 3:30am. We drove to the nearest dealership and I tipped the tow truck driver $60 for his help and patience.

I'm guessing my alternator needs to be replaced. Good thing for extended warranty and AAA


Cushioning my front lip with towels really helped save the front bumper.

 

Been there done that unfortunately. Good thing you have the warranty, or I would have definitely told you to run from the dealership, they will try and charge you $600+ for the same remanufactured alternator that you can buy from NAPA for around $250.

Hope everything goes well, and for anyone reading this who doesn't know, if the red Battery Alternator Visit Workshop light comes on it means that you are running completely off of the battery and your car *will* die in a matter of hours. This is not like an orange check engine light that you can just drive on most of the time.

 

Yeah this is true. The "Battery/Alternator Visit Workshop" error is no joke.
Take the car to the dealer asap if possible. Don't wait and go through any hassles of towing the car.
Especially if you have a lowered vehicle.

I guess several other members have had the same issue.
It seems like these MB alternators don't last that long

 

MOre then likely it won't be the alternator... You may jst need to change the Vol Regulator..Alternator on newer car should last long time...

 

Here is your problem.

https://mbworld.org/forums/c32-amg-c...regulator.html

Good luck.

 

i had mine replaced too. i went with a new MB alternator but it cost me like $800 parts and labor. sadly, mine started giving me trouble at 48,000 miles but didn't die completely till just over 50,000. le sigh....

 

Same thing here when I had mine. It's about $80 for a new one.

 

might be good preventive maintenance if you dont have extended warranty..like me

 

Good to know! Might have to pick one up for the future...

 

This is what happened to me, but because the voltage regulator went bad it killed the alternator.

 

I figured it out-Cannon and 1V8 have the same background in thier sigs....sorry-OT-but it was driving me nuts trying to figure out where I saw those high suspension lines before

 

I had to replace my alt with a new one... My old alt. was fried and produced burning smell. Anyways, I hope you do not run into that... otherwise prepare your wallet for some serious $$$$

 

I just got my car back today. Voltage regulator, Alternator, and Battery had to be replaced. All under warranty

 

Warranty is wonderful.. You prolly saved couple grands..

 

 

Good news, glad your warranty covered it. All the above advice re: voltage regulators is correct. I got stuck on the road with a bad VR on my C43 and just had the VR replaced on my C55 as preventative maintenance (I do not want to get stuck again). This also happened many years ago on my 300E. However, on that car you could replace the VR with a stubby screwdriver on the side of the road, not so on the C55.

 

So uh...how common is the voltage regulator issue?

 

Very common...

 

how hard are these to DIY?

 

Just a word to the wise, having experienced this myself, do not just assume that it is the voltage regulator. It is worth taking the alternator out and feeling/listening to how it is turning. The bearing in my alternator was definitely bad when I got this message.

Also the alternator in our cars are a bit of a PITA to get to, so it would be annoying to take it out, replace the VR, put it back and have to do the whole thing again.

 

Very true, on some MB's you can replace the VR without removing the alternator, on others you can't. I know that the VR on the C55 requires the back of the alternator to be removed which (depending on the tech) may require that the alternator be removed first. I had mine done under warranty and the shop charged the ins. co. 3.4 hours for the job.

 

Same exact thing happend to me. 2005 C55 22K miles and my Low voltage/battery warning came up. Sure enough 1 hour later my entire car shut down while driving. Had it towed to the dealer who told me the voltage regulator needs to be replaced. Should the alternator and battery also be replaced at the same time? They said No, however, they will test both after the regulator is installed to check. All parts are original.

Any advice on whether all 3 parts should be replaced or just the regulator?

 

It's because of this I keep my car on a battery tender every day. A 2005 with 22k miles says the car doesn't get driven very much. The battery in these cars are huge and so even when they are weak, they will still start the car just fine. The problem is, the alternator is working very hard to get the battery recharged fully. After driving mine on a 500 mile trip it still took the tender 12 hours before it went to "float" mode. It's why some guys who use them as daily drivers with 90k miles have never had a charging problem. I have checked mine and when running the alternator puts out 13.8-14V just the way it should.

To answer your question, the alternator is probably fine, just needs a regulator. The battery might not come back from a discharged state or if it does it might not hold a good charge for a long time. A new battery and a tender would be good insurance. I wired mine directly to the battery and so it's real easy, clean, and no screwing around with aligator clips. The battery posts have a threaded bolt that the pre-wire lead drops right onto. Just install a couple of nuts and it's done.

 

I had to leave my car at the service department for 2 days in order to run thorough tests on the voltage regulator, alternator, and battery. In the end, all 3 had to be replaced on my car. Your service advisor and the technician should be running the same kinds of tests. I'm sure they will let you know.

Hopefully you aren't paying too much for the repairs.

 

Thanks a bunch for the information guys!! Luckily, I still am under an extended warranty thus the regulator will be free of charge. The dealer just called me and said the battery tested fine and does not need to be replaced. Ithink I will tell them to change it anyway, considering what happened, and the fact that it is over 5 years old, plus I have never used a "float" or battery tender on it. The dealer wants $300 for the battery, Am I better off purchasing my own and having it installed at an independent mercedes mechanic shop?

As for the alternator, they have yet to install the regulator and will tell me how that looks when complete, however, the mechanic said that based on his experience the alternator should test just fine.

As a preventitive measure should we be changing the voltage regulator every 4-5 years?

The battery tender sounds like a great idea? Do you have more information on which type to buy?

Thanks again for the invaluable info.!!!