MBWorld.org Forums

SL-Class (R231) 2013 on: Discussion on the SL550

SL/R231: Low Voltage can’t figure out

     
Old Nov 10, 2021 | 02:12 AM
Share
  #1  
eblount's Avatar
eblount
Thread Starter
Newbie
 
Joined: Nov 2021
Posts: 13
Likes: 2
SL 550
Low Voltage can’t figure out
Hello,

I have a P0562 code. I have replaced the alternator, the AUX battery and the starter battery is good. I can’t figure out why the low voltage persist. Right headlight occasionally flickers at stoplights after short in town driving. Any help would be appreciated. Thanks!
Reply
1
Old Nov 10, 2021 | 04:38 PM
Share
  #2  
David2244's Avatar
David2244
Junior Member
 
Joined: Apr 2021
Posts: 48
Likes: 8
From: Land of the Prince Bishops
2013 SL350
You say the starter battery is good, has it been tested and proved to be OK.
Reply
0
Old Nov 10, 2021 | 06:10 PM
Share
  #3  
eblount's Avatar
eblount
Thread Starter
Newbie
 
Joined: Nov 2021
Posts: 13
Likes: 2
SL 550
Originally Posted by David2244
You say the starter battery is good, has it been tested and proved to be OK.
Starter battery has been tested and the AUX battery is new.
Reply
0
Old Nov 10, 2021 | 07:03 PM
Share
  #4  
David2244's Avatar
David2244
Junior Member
 
Joined: Apr 2021
Posts: 48
Likes: 8
From: Land of the Prince Bishops
2013 SL350
Is your scan tool capable of resetting fault codes and did you try clearing it after fitting the new components.
.
Reply
0
Old Nov 11, 2021 | 02:30 AM
Share
  #5  
eblount's Avatar
eblount
Thread Starter
Newbie
 
Joined: Nov 2021
Posts: 13
Likes: 2
SL 550
Originally Posted by David2244
Is your scan tool capable of resetting fault codes and did you try clearing it after fitting the new components.
.
Yeah, everything has been reset.
Reply
0
Old Nov 11, 2021 | 08:25 AM
Share
  #6  
David2244's Avatar
David2244
Junior Member
 
Joined: Apr 2021
Posts: 48
Likes: 8
From: Land of the Prince Bishops
2013 SL350
PM sent
Reply
0
Old Nov 19, 2021 | 01:53 PM
Share
  #7  
David2244's Avatar
David2244
Junior Member
 
Joined: Apr 2021
Posts: 48
Likes: 8
From: Land of the Prince Bishops
2013 SL350
Any nearer a resolution?
Reply
0

Trending Topics

Old Nov 19, 2021 | 02:00 PM
Share
  #8  
eblount's Avatar
eblount
Thread Starter
Newbie
 
Joined: Nov 2021
Posts: 13
Likes: 2
SL 550
Originally Posted by David2244
Any nearer a resolution?
nope. Still happening. It only happens when idling or going slow. The new alternator works well apparently. Both batteries are good
Reply
0
MB World Stories

The Best of Mercedes & AMG

story-0

New Electric Mercedes-AMG GT 4-Door Coupe Unveiled: 10 Things You Need to Know

 Verdad Gallardo
story-1

6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

 Verdad Gallardo
story-2

Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

 Verdad Gallardo
story-3

Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

 Verdad Gallardo
story-4

8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

 Verdad Gallardo
story-5

Flawlessly Restored Mercedes 190E Evo II Heads to Auction

 Verdad Gallardo
story-6

Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

 Verdad Gallardo
story-7

Mercedes EQS Gets A Major Update: Everything You Need to Know

 Verdad Gallardo
story-8

5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

 Verdad Gallardo
story-9

Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

 Verdad Gallardo
Old Nov 22, 2021 | 05:51 AM
Share
  #9  
iamahoo1's Avatar
iamahoo1
Newbie
 
Joined: Nov 2020
Posts: 1
Likes: 0
From: Naples, FL
2013 SL550
Are you in key FOB hell?
When you are home, srore all working key FOBs at lease 30 ft away from the car and behind a masonry wall if possible. When I brought my SL550 home from purchase at our local dealer, I hoticed that my CTek battery minder was showing low charge after sitting for a couple days without driving and this with a brand new Merc battery. As long as the zillion+1 system modules, ROM computers and special sensors reporting to the ECU can communicate with FOBs, they just sleep and continue to draw juice from the batteries. Also, get a CTek smart charger and keep it hooked up when not using your SL for a few days to make your tee time or hang at the yacht club. These cars love fully charged batteries and all systems seem to work better when you leave the garage after being attached to the CTek all night.
Reply
0
Old Nov 22, 2021 | 12:42 PM
Share
  #10  
eblount's Avatar
eblount
Thread Starter
Newbie
 
Joined: Nov 2021
Posts: 13
Likes: 2
SL 550
Originally Posted by iamahoo1
When you are home, srore all working key FOBs at lease 30 ft away from the car and behind a masonry wall if possible. When I brought my SL550 home from purchase at our local dealer, I hoticed that my CTek battery minder was showing low charge after sitting for a couple days without driving and this with a brand new Merc battery. As long as the zillion+1 system modules, ROM computers and special sensors reporting to the ECU can communicate with FOBs, they just sleep and continue to draw juice from the batteries. Also, get a CTek smart charger and keep it hooked up when not using your SL for a few days to make your tee time or hang at the yacht club. These cars love fully charged batteries and all systems seem to work better when you leave the garage after being attached to the CTek all night.
Thanks. Not a bad idea. However, I don’t think it’s the key being too close. They are stored a considerable way away. The strange thing is that the voltage on the car now noticeably drops when idling. There is a brand new alternator so it’s not that. I floored it off of a stop light a couple days ago and it is been a lot worse since then.
Reply
1
Old Nov 22, 2021 | 01:59 PM
Share
  #11  
WN1X's Avatar
WN1X
Member
5 Year Member
Community Favorite
 
Joined: Jul 2019
Posts: 138
Likes: 45
From: Rhode Island
2013 SL550, 2017 GLE350, 2018 Audi Q3
Did they check/replace the voltage regulator?
Reply
0
Old Nov 22, 2021 | 02:00 PM
Share
  #12  
crconsulting's Avatar
crconsulting
MBWorld Fanatic!
Photogenic
Liked
Loved
Community Favorite
 
Joined: Feb 2021
Posts: 1,419
Likes: 739
From: Nor-Cal
2020 GLC300 -2014 Sl550 - 1997 SL600
Originally Posted by eblount
Thanks. Not a bad idea. However, I don’t think it’s the key being too close. They are stored a considerable way away. The strange thing is that the voltage on the car now noticeably drops when idling. There is a brand new alternator so it’s not that. I floored it off of a stop light a couple days ago and it is been a lot worse since then.

How are you measuring the voltage drop? Is it the right headlight dimming? Or using your diagnostic scan tool? Does the car start or is it dead after a couple days sitting?
Last edited by crconsulting; Nov 22, 2021 at 02:02 PM.
Reply
0
Old Nov 22, 2021 | 02:01 PM
Share
  #13  
eblount's Avatar
eblount
Thread Starter
Newbie
 
Joined: Nov 2021
Posts: 13
Likes: 2
SL 550
Originally Posted by WN1X
Did they check/replace the voltage regulator?
Isn’t the voltage regulator built into the alternator in this model?
Reply
0
Old Nov 22, 2021 | 02:05 PM
Share
  #14  
crconsulting's Avatar
crconsulting
MBWorld Fanatic!
Photogenic
Liked
Loved
Community Favorite
 
Joined: Feb 2021
Posts: 1,419
Likes: 739
From: Nor-Cal
2020 GLC300 -2014 Sl550 - 1997 SL600
Originally Posted by iamahoo1
These cars love fully charged batteries and all systems seem to work better when you leave the garage after being attached to the CTek all night.

👍 Absolutely
Reply
0
Old Nov 22, 2021 | 02:11 PM
Share
  #15  
crconsulting's Avatar
crconsulting
MBWorld Fanatic!
Photogenic
Liked
Loved
Community Favorite
 
Joined: Feb 2021
Posts: 1,419
Likes: 739
From: Nor-Cal
2020 GLC300 -2014 Sl550 - 1997 SL600
Originally Posted by eblount
Isn’t the voltage regulator built into the alternator in this model?
It’s piggybacked onto the alternator.

Also look at the battery relay module.
"A0009822023"



Last edited by crconsulting; Nov 22, 2021 at 02:49 PM.
Reply
0
Old Jan 23, 2022 | 11:49 AM
Share
  #16  
Bay Leaf's Avatar
Bay Leaf
Member
Liked
Loved
Community Favorite
 
Joined: Sep 2020
Posts: 165
Likes: 33
From: Stockport UK
SL 350 R231
An old thread this I know. What was the outcome. Was it an earth / grounding problem?
Reply
0
Old Jan 25, 2022 | 08:02 PM
Share
  #17  
eblount's Avatar
eblount
Thread Starter
Newbie
 
Joined: Nov 2021
Posts: 13
Likes: 2
SL 550
Originally Posted by Bay Leaf
An old thread this I know. What was the outcome. Was it an earth / grounding problem?
There were like 5 electrical shorts. It was a total pain.
Reply
0
Old Jan 26, 2022 | 05:09 PM
Share
  #18  
David2244's Avatar
David2244
Junior Member
 
Joined: Apr 2021
Posts: 48
Likes: 8
From: Land of the Prince Bishops
2013 SL350
Is it now resolved?
Reply
0
Back to Subforum
SL-Class (R231)
View Next Unread
Tire Pressure Recommendation

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 

Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Rate This Thread
Rate This Thread:
You have already rated this thread Rating: Thread Rating: 0 votes, average.
Show Printable Version
Email this Page

Advanced Search

All times are GMT -4. The time now is 04:50 AM.

story-0
New Electric Mercedes-AMG GT 4-Door Coupe Unveiled: 10 Things You Need to Know

Slideshow: Mercedes-AMG's new electric GT 4-Door Coupe trades combustion for software, synthetic noise, and more than 1,100 horsepower.

By Verdad Gallardo | 2026-05-20 20:08:15


VIEW MORE
story-1
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

Slideshow: Not every Mercedes design becomes timeless, some feel stuck in the era they came from.

By Verdad Gallardo | 2026-05-12 18:09:07


VIEW MORE
story-2
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

Slideshow: Yes, Mercedes built manual cars, and some of them are far more interesting than you'd expect.

By Verdad Gallardo | 2026-05-02 12:36:58


VIEW MORE
story-3
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.

By Verdad Gallardo | 2026-04-29 11:19:28


VIEW MORE
story-4
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

Slideshow: Before curves took over, Mercedes mastered the art of the straight line, and some of those shapes still look right today.

By Verdad Gallardo | 2026-04-25 12:05:49


VIEW MORE
story-5
Flawlessly Restored Mercedes 190E Evo II Heads to Auction

Slideshow: The 190E Evolution II shows how a homologation necessity became a six-figure collector icon.

By Verdad Gallardo | 2026-04-22 17:53:47


VIEW MORE
story-6
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

Slideshow: Mercedes is turning one of its core nameplates electric, and the details show just how serious this shift is.

By Verdad Gallardo | 2026-04-21 13:58:06


VIEW MORE
story-7
Mercedes EQS Gets A Major Update: Everything You Need to Know

Slideshow: Faster charging, longer range, and a controversial steer-by-wire system define the latest evolution of Mercedes-Benz EQS.

By Verdad Gallardo | 2026-04-15 10:35:34


VIEW MORE
story-8
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

Slideshow: These overlooked Mercedes-Benz models never got the spotlight, but they quietly delivered more than most remember.

By Verdad Gallardo | 2026-04-13 19:35:45


VIEW MORE
story-9
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

Slideshow: A well-used 1991 Mercedes-Benz 300D with more than one million miles is now looking for a new owner, and it still appears ready for more.

By Verdad Gallardo | 2026-04-10 10:05:15


VIEW MORE