please visit workshop battery/alternator
05-18-2015, 06:01 PM
#1
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C320
please visit workshop battery/alternator
I have a 2001 C320, My battery alternator light came on out of the blue, I had it and the battery checked the battery was 100% and the alternator was 13.9 idle and 13.7 with all the light on and revving up the engine. I then per the owners manual changed the poly v belt and 24 hours later the light is .Please help.
08-25-2015, 04:36 PM
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C220 CDI Estate 2003
I have had a similar problem with my 2003 C220 CDI which came down to a dodgy plug connection to the ECU located o/s/f under bonnet bulkhead area due to someone in the past not seating the watertight cover back on. i found it by wiggling wiring with the engine running, you can hear the engine noise change as the load from the alternator changes the engine note, or could be an alternator failing as said before
09-03-2015, 03:45 PM
#4
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battery/alternator warning lamp
My 2000 E320 4matic displayed the same light last week. I checked charging system with load and alternator is good as is battery (only a few months old)
Belt is new as well. Did research on another MB site and got a hint about checking Transmission Control Module and possible contamination from trans fluid. Sure enough, TCM had fluid inside of it. I disassembled and cleaned it with electronics cleaner. Also cleaned connectors. Put TCM back and problem solved. A few days later I changed out the pilot bushing on the 722.6 transmission. Known fault for seals to leak and fluid to weep up through harness into TCM! I cleaned the lower connector with electronics cleaner and double checked the TCM. No more fluid problem and have not seen the Battery/Alternator light anymore. I believe the electronic system is monitored for voltage changes or shorts which would trigger the warning lamp. Others have said the transmission fluid inside the TCM could contain small metallic particles thus causing voltage variations that trigger the warning lamp. I would consider checking your TCM and connectors while checking the rest of the system. Brushes/Voltage regulator is another known issue. Bosch units are cheap. Valeo parts are not. Depending on the age of the alternator, a rebuilt might be a better option. Keep in mind the battery must be good. If it's older than 4 years it's suspect. Can't check the charging system with a bad battery. You'll be chasing your tail.
Belt is new as well. Did research on another MB site and got a hint about checking Transmission Control Module and possible contamination from trans fluid. Sure enough, TCM had fluid inside of it. I disassembled and cleaned it with electronics cleaner. Also cleaned connectors. Put TCM back and problem solved. A few days later I changed out the pilot bushing on the 722.6 transmission. Known fault for seals to leak and fluid to weep up through harness into TCM! I cleaned the lower connector with electronics cleaner and double checked the TCM. No more fluid problem and have not seen the Battery/Alternator light anymore. I believe the electronic system is monitored for voltage changes or shorts which would trigger the warning lamp. Others have said the transmission fluid inside the TCM could contain small metallic particles thus causing voltage variations that trigger the warning lamp. I would consider checking your TCM and connectors while checking the rest of the system. Brushes/Voltage regulator is another known issue. Bosch units are cheap. Valeo parts are not. Depending on the age of the alternator, a rebuilt might be a better option. Keep in mind the battery must be good. If it's older than 4 years it's suspect. Can't check the charging system with a bad battery. You'll be chasing your tail.
