GNew

First off, thanks to all who contribute to these forums. The wealth of helpful info has saved me a lot of time and money since I bought my 2005 C230K four years ago.

Here it goes... A few weeks ago the "Battery/Alternator Visit Workshop" message appeared and has continued to appear almost every other time I drive the car. This past weekend the same message appeared along with dimming of some interior lights and showing the "ESP Not Available Visit Workshop" and "SRS Malfunction Drive to Workstation". As I understand, the ESP and SRS soon following the Battery/Alternator message is typically a sign of a failing alternator and/or voltage regulator (correct me if I'm wrong). I immediately parked the car but left it running. After 10+ minutes at idle the interior lights returned and ESP and SRS message went away. I got the alternator tested and was told the diodes were good but the regulator was faulty. I replaced the voltage regulator on the back of the alternator (both Valeo) along with thoroughly cleaning the slip rings. The car is running fine until earlier today the check engine light came on showing codes P0620 (Generator Circuit Control Malfunction) and P0562 (System Voltage Low). The Battery/Alternator message is still on even after replacing the voltage regulator.

In addition, the "Brake Wear Visit Workshop" message appeared approximately 1 month prior to the above mentioned messages/codes. Just throwing that out there in case it may be related to any of these issues.

Any advice on what should be replaced or possible connections to check?
Thanks guys.

VVF

What's the battery voltage though? Maybe your battery is dying.

Brake wear message means your front brake pads are "worn out".
But, depending on your driving style, you can probably still drive a couple thousand miles on the old pads.

GNew

Battery by itself is at 12.75v. At idle it dropped to 12.35v (constant) with no accessories engaged.

BigN8

That seems very low to me.

I would loadtest your battery.

VVF

Resting voltage of 12.75v is quite healthy.
At idle it should rise to ~13.6v.
Load test won't hurt though, but it seems the charging system is the problem.
Since you've replaced the regulator, I would suspect the alternator itself now...
It is weird that the battery is fully charged, with a dying alternator O_o

02C230C Lebanon

I started getting the warning few days ago only on cold starts, and if I'd turn it off within less than a minute & restart it, I still get the warning, but if I'd warm/drive it for a minute or more, turn it off then, restart it, no warning, so I changed the regulator, but the problem persisted. What could the reason be, knowing that I tested the less-than-a-year old battery and it's fine? When I don't get the warning, the power is around 14.25V

BigN8

New alternator is most likely going to be needed.

I have heard a lot of mixed reviews on the voltage regs being replaced.

VVF

What is the voltage when the car is off, and what is the voltage when ignition is on before and during cranking?

14.25 when running sounds like normal charging voltage.

02C230C Lebanon

But then why would it appear only on cold starts? Could it be the diodes or dirty contacts under brushes? Or a bad connection with humidity/rust? Can the diodes be changed on a Bosch alternator?

VVF

When do you get the warning? While starting?
So far it sounds like your battery is weak. In cold weather the battery capacity drops some more, hence the warnings, IMHO.

02C230C Lebanon

I can't remember what was the voltage, but it was fine.
When I get the warning is usually like seconds after a cold start, the voltage at battery on idle is around 12.20 as I recall, and if I turn it off & restart it without getting the warning, the voltage goes up directly to 14.25V

02C230C Lebanon

Okay, I changed the whole 90 Amps alternator with one from the scrapyard for $100, as mine's bearings were starting to sound bad, and now everything seems fine. I was offered to replace it with a 120 Amps for $160, but I preferred not to. I kept the new regulator I had replaced on the old alternator

wvadam

Hi, did this fix your problem?

I did the same thing, still had the warning, then replaced the regulator, and still had the problem. Each of these attempted fixes only lasted a few days because unplugging the battery reset the warning only to come back on later. I am currently looking into the chassis ground connections being the culprit.

02C230C Lebanon

Problem solved so far

sinape62

After start, the amps used to draw the starter to crank the motor is significant enough. Think about the energy it takes to crank the motor? The Alternator through the voltage regulator/(reverse current relay/diode) trickle charges the batter after start. The message you were seeing was that the Alternator was not charging the battery after the current draw. Windings in the alternators, springs and or worn brushes, bad/ worn commutator can cause alternator issues; including bearing issues/ corroded cables. Battery is only needed during start. Once the engine is running the Alternator provides electrics.

VVF

Then how do you explain that after restarting the car he had 14v?

02C230C Lebanon

It's the voltage/power provided by the alternator

BigN8

The alternators are not that expensive so I just replaced that instead of getting the wrong/bad/who knows what voltage regulator.

sinape62

Exactly.

apatchi83

Hello everybody, I had the same error message on my dash of my 2004 C230 Kompressor, I bought a new alternator from AutoZone and installed it, after I was done I tried to start the car, I was surprised that the alarm had stopped working in addition the ignition wont make the "click" noise anymore like it normally does when you insert the key, I thought I blew up a fuse but after checking all fuses are ok, I cant plug a scanner to see if there are any codes stored because I cant turn the key at all. In addition, if I leave the key in ignition and open drivers door, the cluster will illuminate showing trip mileage, time and outer temperature but odometer will show " -------" , anybody had something like this before ?!!!!!