Alternator fault 109A00 - w212 E350 cdi

[b21playa]

It could be that the regulator itself is not bad, but the worn-out brushes are barely long enough to touch the slip rings, so intermittent contact. In my case I think it was both.

Do a few hard braking events in a row, checking for consistency. Not full stop, but enough speed loss to downshift a couple gears.

Thanks. All was going well and on my way home after around 15miles light came on. As I need the car I’ve just ordered a used alternator to swap out and see how it goes. I can then get mine bench tested and refurbished if needed. It’s supposed to arrive tomorrow, so will be stripping the car and removing the old one in the morning

 

[gusferlizi]

Thanks. All was going well and on my way home after around 15miles light came on. As I need the car I’ve just ordered a used alternator to swap out and see how it goes. I can then get mine bench tested and refurbished if needed. It’s supposed to arrive tomorrow, so will be stripping the car and removing the old one in the morning

Inspect the used one before installing. Won't hurt to clean debris from the regulator brushes and clean all the contacts with a scouring pad

 

[gusferlizi]

Thanks, I see what it looks like. Where is it located, is it simply accessible?

As far as I can tell it fits inside the HVAC box. Dash out job

 

[AEKostas]

Thanks, you have been most helpful. Not one for me, alas, and it sounds expensive and creak-inducing.

 

[gusferlizi]

Thanks, you have been most helpful. Not one for me, alas, and it sounds expensive and creak-inducing.

I don't think the heater cell can fail without an error saying it is faulty btw. It would be more likely to have an alternator issue

 

[AEKostas]

I don't think the heater cell can fail without an error saying it is faulty btw. It would be more likely to have an alternator issue

Well, not an easier fix that.

 

[b21playa]

Inspect the used one before installing. Won't hurt to clean debris from the regulator brushes and clean all the contacts with a scouring pad

Will do. I’ll compare them both before installed used one. Will also give it a quick blast with the air compressor

 

[b21playa]

Right alternator off (not easy) and looks like the cause was worn regulator brushes. Part didn’t arrive today so a waiting game until it arrives. Will check brushes on that as well

 

[gusferlizi]

Right alternator off (not easy) and looks like the cause was worn regulator brushes. Part didn’t arrive today so a waiting game until it arrives. Will check brushes on that as well

Yep, there's your problem. I'm pretty sure the regulator electronics go bad as well...

 

[b21playa]

Yep, there's your problem. I'm pretty sure the regulator electronics go bad as well...

I thought the same. Trying to get a new regulator locally (KMS parts) for the used alternator

 

[AEKostas]

Well, not an easier fix that.

I just had a thought: is the diagnosis simple enough?

 

[b21playa]

Turns out used alternator was incorrect even though parts catalogue showed as being correct so that’s gone back and I’ll just order a reconditioned alternator. Regulator was available until end next week anyway

 

[AEKostas]

What a palaver... Hopefully you will sort it out soon enough.

 

[b21playa]

What a palaver... Hopefully you will sort it out soon enough.

I know. Hopefully by next weekend the new one arrives and I can fit it

 

[b21playa]

Finally got the new alternator in and back to normal

 

[gusferlizi]

Finally got the new alternator in and back to normal

Great. I wonder if braking performance has improved for you as well

 

[b21playa]

Great. I wonder if braking performance has improved for you as well

I didn’t notice anything different when I took it out earlier

 

[gusferlizi]

I didn’t notice anything different when I took it out earlier

Interesting. Both my E320 and my CLK240 had a major improvement.

 

[b21playa]

Interesting. Both my E320 and my CLK240 had a major improvement.

Maybe different on the w212 chassis

 

[b21playa]

Just to update; been using the car 3 days now and not had an issue. Thanks for all the help

Just need to change thermostat as it’s not keeping temperature stable when heaters are on…luckily a lot easier to do than the alternator