E-Class (W211) 2003-2009

Electronic Problems

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old Apr 11, 2018 | 07:47 PM
  #1  
edtse88's Avatar
Thread Starter
Junior Member
 
Joined: May 2016
Posts: 34
Likes: 0
2003 E320
Electronic Problems

I'm having electronic problems that have been giving me a headache lately. A timeline:
Convenience functions turning off issue. I thought it was voltage regulator
Replaced voltage regulator
New issue shows up, the red battery indicator comes up once in awhile, after driving awhile. Convenience function still shows up. Car starts up fine.
Thought maybe I just needed to drive it a bit to charge the battery but now ABS, ESP error stays on. Cruise control also doesn't work anymore.
Reduced brake function light also comes on once in awhile now, sometimes stays on longer, sometimes just blinks. Also reduces power probably due to the brake issue. I'm assuming its something to do with the auxiliary but I had it tested and they said it was fine even though the guy has never tested an auxiliary battery before.
Also I noticed that my headlights flicker especially on startup.
The scanned codes I am getting are shown below. Before I buy a new relay, what else do you guys think could be the problem? Alternator, BCM, fuses, some kind of connector issue?
The issues seemed to have gotten worst since I replaced the VR, before it was only the convenience functions. Is it something I did?

Cheers,
Ed


Reply
Old Apr 11, 2018 | 08:19 PM
  #2  
rapidoxidation's Avatar
MBWorld Fanatic!
 
Joined: Jan 2016
Posts: 2,748
Likes: 880
From: In the Shadow of the Tetons
2013 ML350 Bluetec
How old is your aux battery? If it is more than 5 years, put a fresh one in.
Reply
Old Apr 11, 2018 | 08:53 PM
  #3  
edtse88's Avatar
Thread Starter
Junior Member
 
Joined: May 2016
Posts: 34
Likes: 0
2003 E320
I'll have to check but it's definitely more than 4 years. I just charged the the auxiliary battery and all the errors have gone away when I drove around for 10km. I also took out the alternator to clean all the contacts. I should have done that when I changed the voltage regulator. We'll see how it goes. I'll report back once I get a chance to run down the auxiliary battery if its not charging correctly.
Reply
Old Apr 29, 2018 | 11:46 PM
  #4  
edtse88's Avatar
Thread Starter
Junior Member
 
Joined: May 2016
Posts: 34
Likes: 0
2003 E320
I've driven the car another 1000km now and it seems fine. No convenience function disabled or anything. There was one day where the ESP/ABS/Cruise Control was disabled but it went away after restarting my car.

In conclusion, the initial problem was the voltage regulator but when I changed it, it must not have been making good contact with the alternator. So if you ever change your voltage regulator, brush off any corrosion on any contact points. I just used a brass wire brush.
Reply

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


You have already rated this thread Rating: Thread Rating: 0 votes,  average.


All times are GMT -4. The time now is 12:45 AM.

story-0
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-1
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-2
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-3
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-4
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-5
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-6
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-7
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-8
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
story-9
10 Most Reliable Mercedes-Benz Models You Can Buy Used

Slideshow: From bulletproof sedans to surprisingly tough SUVs, these Mercedes models proved that the three-pointed star can go the distance.

By Verdad Gallardo | 2026-04-08 09:55:49


VIEW MORE