Mercedes w203 2001 Undervoltage Consumer Defective

[Ars19]

Greetings,

First, I apologize if any similar thread already exists.

I have a Mercedes-Benz model W203 Year: 2001. Diesel, Automatic. CDI 220. 2.2

Lately, I'm receiving a message about Undervoltage Consumer Defective, after 2-3 minutes, when I start the vehicle in the morning. It is not a red warning, just in normal color. But after 20-30 minutes, when the vehicle reaches 60 Degree Celsius (more or less), the message disappears and I can see the lights of the dashboard become brighter. I can tell the vehicle is charging normally.

I would like to hear your opinion on this matter before I visit the workshop.

I have made some research on the internet and I have learned that the alternator is the last thing that needs to be changed.

First, I need to replace the voltage regulator; I guess.

But what it could be, and why does the vehicle charge when it reaches a certain temperature?

thank you.

 

[Tony Dyson]

The temperature rise may be coincidental in line with time the battery is being topped up after an engine start?

Measure the battery voltage first thing in the morning before you start the car, 12.6v is ideal 12.4 or below isn't!
Then start the car and measure again, fluctuations between 13.5v-14.8v should be available.

The first will confirm the state of charge after a night's rest, the second, the output of your alternator.

 

[mioba]

Consumers such as COMAND shut down or you get a warning due to low battery same with things like pre safe.

Stick a charger on the battery for the night and you will be good to go, then take it from there, test battery voltage.

How old is the battery - stamped on a terminal week and year?

 

[Ars19]

Thank you, Tony Dyson and mioba for your prompt reply.

The battery is brand new. I just replaced it a couple of months ago.

I'll try to measure the voltage through the menu (if that's possible in this car model).

Thank you.