Battery-Alternator Warning Light - Where should I look for damage?
Newbie
Joined: Aug 2022
Posts: 1
Likes: 0
From: Santiago, Chile
C200 Kompressor
Wish me luck
Hi, my name is also Kevin and I just caused a short (with a wrench) while trying to check an oxygen sensor.
A spark came in and after turning on the car, the same battery - alternator red message spawned and my scanner threw the same error code as yours...
First step I'm gonna do is take off the Alternator and replace the voltage regulator, in addition to checking the starter-alternator wire and its resistance.
This post indeed will serve me well... Thanks for providing detailed information.
I hope I won't have to mess with the ECU - SAM wiring, GOD PLEASE!
Wish me luck!
A spark came in and after turning on the car, the same battery - alternator red message spawned and my scanner threw the same error code as yours...
First step I'm gonna do is take off the Alternator and replace the voltage regulator, in addition to checking the starter-alternator wire and its resistance.
This post indeed will serve me well... Thanks for providing detailed information.
I hope I won't have to mess with the ECU - SAM wiring, GOD PLEASE!
Wish me luck!
Last edited by kevarefer; Aug 14, 2022 at 01:33 AM.
Thread Starter
MBWorld Fanatic!
Joined: Jul 2017
Posts: 1,004
Likes: 148
From: Richmond, VA Metro Area
2005 C230 Sport Sedan-6 Speed Manual
I think I know how you feel. As you can see from this thread, I made several mistakes before I eventually repaired the problem. The biggest mistake was allowing the dealer to replace the ECU. I can't prove it, but I don't think it was necessary and it was costly. Here are my observations and suggestions based on this costly learning opportunity:
1. Check to see whether the alternator is charging. Unless there is a difference between the cars MB sells in Chile and the cars it sells in the U.S. you can do this through the menus that display on the dashboard. If it is not charging at all, you should have your alternator tested. If it is damaged, you can go ahead and change the voltage regulator or the alternator or the entire alternator. However, I would be surprised if that fixed the problem. The reason I say this is that if you made the same mistake I did, the fuse in the battery-alternator-starter cable probably blew. See Russell Ormerod's comment in post #11 of the thread.
2. If you did blow the fuse, you will likely need to replace the battery-alternator-starter cable. I looked at the fuse and couldn't think of a way to replace it that I thought would be reliable. See post #22 from Russell confirming that replacing the cable is the best option.
3. If you replace the battery-alternator-started cable and the car starts charging, you may still have an error message. If that is the case, you may need to replace the alternator. You should also consider running a new wire form the alternator to pin #47 on the ECU connector. (See post #111 and later in the thread.)
I am sorry this happened to you, and I hope you have an easier and less expensive experience repairing the damage.
Good luck.
1. Check to see whether the alternator is charging. Unless there is a difference between the cars MB sells in Chile and the cars it sells in the U.S. you can do this through the menus that display on the dashboard. If it is not charging at all, you should have your alternator tested. If it is damaged, you can go ahead and change the voltage regulator or the alternator or the entire alternator. However, I would be surprised if that fixed the problem. The reason I say this is that if you made the same mistake I did, the fuse in the battery-alternator-starter cable probably blew. See Russell Ormerod's comment in post #11 of the thread.
2. If you did blow the fuse, you will likely need to replace the battery-alternator-starter cable. I looked at the fuse and couldn't think of a way to replace it that I thought would be reliable. See post #22 from Russell confirming that replacing the cable is the best option.
3. If you replace the battery-alternator-started cable and the car starts charging, you may still have an error message. If that is the case, you may need to replace the alternator. You should also consider running a new wire form the alternator to pin #47 on the ECU connector. (See post #111 and later in the thread.)
I am sorry this happened to you, and I hope you have an easier and less expensive experience repairing the damage.
Good luck.
