W203 ‘Visit workshop battery/alternator fault’
07-01-2019, 05:01 PM
#1
Newbie
Thread Starter
Join Date: Jul 2019
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
Range Rover/ c class / astravan
W203 ‘Visit workshop battery/alternator fault’
Hi guys and girls...
This is my first post here, I may reopen some old wounds 😬as I have been reading a few post’s from years back.
I have here my brother-in-laws
2003 W203 C180 kompressor auto with the dreaded ‘battery/alternator visit workshop’ in RED......
Could anyone confirm where the Engine ECU get’s the signal for voltage of the battery/charge rate, when I’m reading live data (engine running) the battery voltage is fluctuating between 14.4 - 8.6 with or with out load, but at the battery (which is new) 14.5 idle with/wo load and the same at the back of the alternator!
I have limited access to software but use Delphi.
am i right in thinking it’s the front SAM?
anyway to confirm?
Thanks in advance
This is my first post here, I may reopen some old wounds 😬as I have been reading a few post’s from years back.
I have here my brother-in-laws
2003 W203 C180 kompressor auto with the dreaded ‘battery/alternator visit workshop’ in RED......
Could anyone confirm where the Engine ECU get’s the signal for voltage of the battery/charge rate, when I’m reading live data (engine running) the battery voltage is fluctuating between 14.4 - 8.6 with or with out load, but at the battery (which is new) 14.5 idle with/wo load and the same at the back of the alternator!
I have limited access to software but use Delphi.
am i right in thinking it’s the front SAM?
anyway to confirm?
Thanks in advance
07-04-2019, 01:03 PM
#3
MBWorld Fanatic!
Try connecting the multimeter from the positive terminal on the battery to the ground not across the terminals. Then set your multimeter to dc volts and ‘record’, then rev and hold the throttle a few times. If you have a powerful aftermarket amp, crank that up too. This should tell you reliably if you have a drop in voltage even for a split second.
Chance are, it’s your alternator. Look for a local starter and alternator shop. Take your alternator there instead of buying a new one. You should be able to get it fixed for under a $100. I’ve fixed the alternators on my CLK55, E320, ML320 twice, and now my C240 just today.
If the the car is loosing voltage while off, it’s always the battery. If it losing voltage while running, it’s the alternator or corroded leads.
Chance are, it’s your alternator. Look for a local starter and alternator shop. Take your alternator there instead of buying a new one. You should be able to get it fixed for under a $100. I’ve fixed the alternators on my CLK55, E320, ML320 twice, and now my C240 just today.
If the the car is loosing voltage while off, it’s always the battery. If it losing voltage while running, it’s the alternator or corroded leads.
