2010 G350 CDI issues help required
Recently, 2010 G350 CDI has two issues.
1.Random times in cold morning when try engine on using key and I can hear keep cranking noise, but completely engine on. After 2-3 times repeated engine get started on. After cranking 1-2 times, get black smoke blows out from exhaust.
2.When try to engine on using key nothing happens, keep repeated 2-3 times engine started on. It is separately happens, not related to issue #1.
Benz dealer done diagnostic job and asked to order conductor replacement + replace key system together.
Is it correct diagnostic, service?
Really, want to hear forum experienced people?
Thanks,


