Under voltage consumer defective
Senior Member
Joined: Jan 2010
Posts: 456
Likes: 4
From: Canada
2003 c240 4matic wagon
how old is your battery?
acess dyno mode and read the voltage with the car off and on 12.6 to 13 volts or so battery is good with car off with engine on should be 13.5 to 14.5 volts if not the the alternator my be bone
dyno mode put the display on your odometer turn key off turn key to position 1 and press the odometer reset buttom 3 times it will beep and show your voltage
or if you have a voltage meter read the battery voltage engine off and on
acess dyno mode and read the voltage with the car off and on 12.6 to 13 volts or so battery is good with car off with engine on should be 13.5 to 14.5 volts if not the the alternator my be bone
dyno mode put the display on your odometer turn key off turn key to position 1 and press the odometer reset buttom 3 times it will beep and show your voltage
or if you have a voltage meter read the battery voltage engine off and on
Super Member
Joined: Jun 2005
Posts: 651
Likes: 5
From: So. Cal.
'02 C320 Wagon, '78 308 GTS, '06 Highlander Hybrid
Yep, that's what mine was when I got that message. I did check the battery and it was OK. FYI, after my wife got this message, the alternator lasted only a couple more days, when it finally failed and left her stranded.
MBWorld Fanatic!
Joined: Oct 2006
Posts: 4,856
Likes: 4
02 C32 AMG
monitor your voltage through the secret A/C menu.
your running voltage should be at least in the mid-high 13s if not the low 14s.
is the car quick or slow to turn over? do you drive it daily? if you don't drive it for a day or two, is it slower to turn over?
alternators are generally good for about 85k on the W203s. you can go to autozone and they can load test your battery and alternator (generally for free).
if those are good, it is ALSO possible that you have a bad ground. this incident happened to my car. i had a new battery. i replaced the alternator. that didn't fix the issue. i replaced the internal voltage regulator in the new alternator (i heard those tend to be faulty)...THAT didn't fix it. finally, took some cheap speaker wire and added an engine ground: all problems solved
Member
Joined: Jan 2013
Posts: 76
Likes: 1
2002 MERCEDES BENZ C320
ACCESS DYNO MODE MB C320
I followed steps to chk the voltage , I did not get it to show up in window
While in odometer display , turn key to position1 , press reset button 3 times , read voltage ???? I am I doing it right ? any help ?
While in odometer display , turn key to position1 , press reset button 3 times , read voltage ???? I am I doing it right ? any help ?
how old is your battery?
acess dyno mode and read the voltage with the car off and on 12.6 to 13 volts or so battery is good with car off with engine on should be 13.5 to 14.5 volts if not the the alternator my be bone
dyno mode put the display on your odometer turn key off turn key to position 1 and press the odometer reset buttom 3 times it will beep and show your voltage
or if you have a voltage meter read the battery voltage engine off and on
acess dyno mode and read the voltage with the car off and on 12.6 to 13 volts or so battery is good with car off with engine on should be 13.5 to 14.5 volts if not the the alternator my be bone
dyno mode put the display on your odometer turn key off turn key to position 1 and press the odometer reset buttom 3 times it will beep and show your voltage
or if you have a voltage meter read the battery voltage engine off and on
Junior Member
Joined: Dec 2013
Posts: 66
Likes: 12
From: Greenville, SC
2003 W203 C230K
Are you pressing it 3 times fast? It won't work if you don't do it fast enough. Press the button 3 times within about 1 or 2 secs. Upon doing this, you should hear one beep as the voltage is called up to the screen. This is also the menu where you can scroll through to check actual engine oil level (within one tenth of a liter accuracy) and activate dyno mode.
