2006 e320 alternator/BCM/relay? problem
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e320
please delete - double posted
need help- 2006 e320 with 339,000 miles on it, 90% sure it had the original alternator
BCM and relay replaced i think 7 years/140,000 miles ago
got the red light and used icarsoft to show 9055
took it to a good mercedes independent in tucson and they diagnosed bad alternator
replaced that and the belt -supposedly it drove fine for 10 miles then the light came back on
they ran star and say it needs a new bcm
new codes now 2248-4 and 2249-4 check G2 generator- these were not here before the alternator was replaced
i pulled the BCM to check for corrosion and it is pristine on the plug and inside the BCM
this car has a base model edge monitor plugged into obd port reading a few parameters one of which is real time voltage so i can watch everything, i know exactly when it is charging and not
not sure what to think
i picked the car up from the shop because i can do a BCM myself and it would just be sitting there until tuesday
Initially was running 13.9-14 on the edge monitor, in 3 miles it dropped to 12.4 like something is clicking off
took it back and they said bad bcm again, i am guessing they are scanning it with the star machine
what i dont understand is i thought bcm did not control main battery charging only aux battery
so i have driven the car around some the last couple of days in town and on the hwy trying to watch what it is actually doing
sometimes it is fine
if the charging voltage drops off 50% of the time i can increase rpms and get the charging to kick back on and run 13.8-14 for 30 minutes or until i shut it off
then sometimes that does not work
this seems to me more like a voltage regulator than bcm???? but i dont know
it will run, start and stop fine for 30-40 minutes and then i can watch it start dropping and go down to 12.2-12.4 etc
sometimes turning the car off and back on makes it charge again sometimes it just starts again on its own
it has to be dropped to 12.2 for a bit before it pulls the red dash visit workshop code, sometimes it will drop and then kick back in itself and no red light comes on
i am debating just replacing bcm and the relays- confused on the relays is it K57 or K75 or both?
also does anyone know the last interation of the bcm?
i ask husker for one and they said no longer available and gave me this number which all the sites say are not compatible with my car 251 545 37 32
the one in the car now is 211 540 86 45
would like to try and buy the newest one
any input on all this would be great
BCM and relay replaced i think 7 years/140,000 miles ago
got the red light and used icarsoft to show 9055
took it to a good mercedes independent in tucson and they diagnosed bad alternator
replaced that and the belt -supposedly it drove fine for 10 miles then the light came back on
they ran star and say it needs a new bcm
new codes now 2248-4 and 2249-4 check G2 generator- these were not here before the alternator was replaced
i pulled the BCM to check for corrosion and it is pristine on the plug and inside the BCM
this car has a base model edge monitor plugged into obd port reading a few parameters one of which is real time voltage so i can watch everything, i know exactly when it is charging and not
not sure what to think
i picked the car up from the shop because i can do a BCM myself and it would just be sitting there until tuesday
Initially was running 13.9-14 on the edge monitor, in 3 miles it dropped to 12.4 like something is clicking off
took it back and they said bad bcm again, i am guessing they are scanning it with the star machine
what i dont understand is i thought bcm did not control main battery charging only aux battery
so i have driven the car around some the last couple of days in town and on the hwy trying to watch what it is actually doing
sometimes it is fine
if the charging voltage drops off 50% of the time i can increase rpms and get the charging to kick back on and run 13.8-14 for 30 minutes or until i shut it off
then sometimes that does not work
this seems to me more like a voltage regulator than bcm???? but i dont know
it will run, start and stop fine for 30-40 minutes and then i can watch it start dropping and go down to 12.2-12.4 etc
sometimes turning the car off and back on makes it charge again sometimes it just starts again on its own
it has to be dropped to 12.2 for a bit before it pulls the red dash visit workshop code, sometimes it will drop and then kick back in itself and no red light comes on
i am debating just replacing bcm and the relays- confused on the relays is it K57 or K75 or both?
also does anyone know the last interation of the bcm?
i ask husker for one and they said no longer available and gave me this number which all the sites say are not compatible with my car 251 545 37 32
the one in the car now is 211 540 86 45
would like to try and buy the newest one
any input on all this would be great
Last edited by clvincent; Jan 1, 2023 at 02:54 AM. Reason: double post
