[lowd239]

More issues with new parts! Its getting old venting about this but it sure is frustrating.

My original alternator suddenly went out a few weeks ago so I hurried and bought a 180 amp Denso 2106207 Alternator from Rock Auto.

In another post I've discussed my issues with codes 29F4 and 29F5 relating to the catalyst and o2 sensors...so I've been checking the codes regularly.

The codes 2E83, 2E85 and 2E8B have continued to reappear numerous times after clearing them. I was spooked that the OEM water pump that I had replaced 80k had gone bad but after doing some research...its appears that others who have recently replaced their alternator had the same codes reoccurring.

https://www.jb4tech.com/forum/model-...ion/n54/33827-

https://www.e90post.com/forums/showthread.php?t=1920098

I'm not happy a happy camper as there were limited options for new 180amp and Denso was the most name brand.

Sounds like its down to it being a non "Bosch" alternator but thats pretty crappy to not be able to trust name brand parts work anymore.

I'm kinda stuck because rockauto would only let me warranty the part and that'd be another Denso alternator. Any thoughts on letting the codes be or maybe try replacing the voltage regulator on the Denso??

Thanks!

[TunafishE93]

Have you looked at the IBS itself, they are known to go bad and with the original failed alternator might have took the IBS with it.

[StradaRedlands]

It might be the fault of the Denso.
Valeo, Bosch or SEG is the general rule.

[lookalikehuuh]

I can almost 100% guarantee its because you installed a Denso alternator. While F chassis BMWs do have Denso units, the E90 platform for the most part have either Valeo or Bosch (now SEG) alternators in them. It is ABSOLUTELY CRITICAL that you install the EXACT same model that came out of the car with alternators.

Unplug your alternator's BSD bus wire and see if that brings the water pump, IBS and oil sensor back online. It is likely that alternator is creating a ton of noise on the BSD bus, and knocking the rest of the systems offline.

This is the correct part: https://www.fcpeuro.com/products/bmw...e-0121-715-112

If for some reason you prefer to buy it from rock auto, this would be the one: https://www.rockauto.com/en/moreinfo...t=2412&jsn=641

The parts above are just an example of what likely goes in your car... but you really do need to match the new part to what you have removed from the car.

I would absolutely call up rock auto and ask them how many Denso alternators they would like to receive back as warranty units, since none of them are going to be fully functional on your car, in fact not only are they not fully functional, but they are causing the water pump, IBS and oil level sensor to "break" in communication potentially putting your car's engine at risk of overheating or running low on oil.

As far as replaceing the voltage regulator on its own... I don't know if the Bosch unit will be fully compatible with the Denso alternator, but if you have no other choice, it might be worth giving it a shot. In fact a new voltage regulator might just fix your old alternator as its a very common reason on why alternators stop working... the brushes just wear out.

Confirm from your original alternator, but it should be: https://www.fcpeuro.com/products/bmw...sch-f00m346089

[mainbearing]

Besides other electrical bus issues others said, looks like Denso only makes Reman alternators. Maybe a bad rebuilt? Maybe return it and get a new Bosch/SEG (if that was what came with the car).

Brand was a concerns when time will come to replace my alternator. I was looking in preparation for a new TYC, but thought the BMW alternator works very closely with the car computer that I would be reluctant to use anything other than the Bosch (SEG) that is in there now, as much as I despise Bosch.

Originally Posted by lowd239

My original alternator suddenly went out a few weeks ago so I hurried and bought a 180 amp Denso 2106207 Alternator from Rock Auto.

[lowd239]

Thanks for all the replies.

Pretty wild to me name brand companies are selling parts that arent fully compatible...did they do any end testing of the product??

This is where the rockauto buying experience is biting me in the ass big time. They are only an online company with no phone number and only a "warranty replacement" is offered to me online...its 3 days over their 30 day return policy and also I no longer have the original packaging. Big damn. I dont want a warranty replacement if thats just going to do the same thing.

I was thinking my only option is calling Denso to see if there is anything they can do. Maybe they will stand by their product and offer options??

Originally Posted by lookalikehuuh

Unplug your alternator's BSD bus wire and see if that brings the water pump, IBS and oil sensor back online. It is likely that alternator is creating a ton of noise on the BSD bus, and knocking the rest of the systems offline.

I'll try this just to confirm...but I think you're right...from what I read it definitely feels like it is the Denso alternator...I just now need to figure out next steps.

[Mike K]

Maybe move ahead with the proper $ alternator, and then open a dispute with Paypal or your CC company with Rock for supplying a faulty product? I have returned stuff to Rock within the window but ended up with a store credit.

[mainbearing]

Rockauto's automated system sucks, but in most cases ok if there are no problems. Even returning that Denso might cost you return shipping, although discounted getting a label on their site. I always keep all packaging material in case things like this happen. Then local parts stores start to look pretty good.

Part of the problem may be BMW using different brands that may not be fully compatible. Densos seem to show up more on the N54?? I was careful in cross referencing my junk Bosch coil to one of the 3 different Delphi coils.

Anyway, if you end up stuck with that thing might just want to get a warranty replacement regardless, in case that one really is defective.

For your next one just get a new Bosch from FCP.

Originally Posted by lowd239

This is where the rockauto buying experience is biting me in the ass big time. They are only an online company with no phone number and only a "warranty replacement" is offered to me online...its 3 days over their 30 day return policy and also I no longer have the original packaging. Big damn. I dont want a warranty replacement if thats just going to do the same thing.

[StradaRedlands]

Originally Posted by mainbearing

For your next one just get a new Bosch from FCP.

I was burnt by FCP once, and am still bitter over it. They had two alternators listed as working on my car, so I bought the cheaper, lower amperage one. That was the wrong one, and while they would take it back, I had to pay the $50 shipping to get it back to them. "You should have known which you needed" was their BS response. Yeah, that's why I checked your stupid site for! I went ahead and got it on Amazon to save $50 or so. Of course that Bosch unit went bad and I had to replace it... from FCP LOL.

[lordnikon]

I ordered a Valeo alternator, made in Poland from Rock Auto about 3 years ago. It's been running fine. Previously the car had a Bosch one but the reman ones are made in China.

[lowd239]

Originally Posted by lordnikon

I ordered a Valeo alternator, made in Poland from Rock Auto about 3 years ago. It's been running fine. Previously the car had a Bosch one but the reman ones are made in China.

Really? And its not throwing any hidden codes?

[lowd239]

Well I may have lucked out. I started a warranty replacement through Rockauto and for some reason their system said "a replacement part cannot be delivered but a refund will be offered for the returned part". So that saves me the drama of going with another Denso unit but its still costing me return shipping which sucks.

I found this Valeo unit on amazon which is a much better price than on Rockauto so I'm ordering this one.

https://www.amazon.com/Valeo-439560-...f-cd087fee0848

[StradaRedlands]

Perfect!!!

[lookalikehuuh]

Originally Posted by lowd239

Well I may have lucked out. I started a warranty replacement through Rockauto and for some reason their system said "a replacement part cannot be delivered but a refund will be offered for the returned part". So that saves me the drama of going with another Denso unit but its still costing me return shipping which sucks.

I found this Valeo unit on amazon which is a much better price than on Rockauto so I'm ordering this one.

https://www.amazon.com/Valeo-439560-...f-cd087fee0848

Did your car originally have a Valeo unit? I thought only the very early cars came with Valeo Units. If your car came with a Bosch unit, you NEED to replace it with a new Bosch unit. unless you want the exact same issues. Just FYI, Bosch no longer makes "new" alternators since they sold/spun off their starters and alternator line to SEG automotive. So a new SEG unit would also work great since that is techniclaly the same unit now.

https://www.fcpeuro.com/products/bmw...e-0121-715-112

Just buy it from a reputable source like FCP Euro, ECS tuning, Pelican parts etc. Not crappy Amazon with the chances they could be counterfeit. It a "better" price for a reason...

StradaRedlands literally just shared a story of his Amazon sourced Bosch unit failing and having to eventually source it from FCP... just do it right the first time.

Also when you are paying for shipping back to someone use a site like https://www.pirateship.com/. They will give you discounted UPS and Fedex rates compared to going to the USPS/FedEx/UPS store directly. A lot of times it will be like 50% cheaper to ship thru them. I have used them dozens of times to ship packages back to FCP and to family members.

[tlow98]

Dumb question - is the only way to tell if you have a Vlaeo or Bosch just to pull it or take a peak with a mirror?

[lookalikehuuh]

Originally Posted by tlow98

Dumb question - is the only way to tell if you have a Vlaeo or Bosch just to pull it or take a peak with a mirror?

I think the mirror is probably the easiest method.

I personally use one of these mirrors with lights on them:

https://www.amazon.com/Telescoping-S...1zcF9hdGY&th=1

[lordnikon]

The sticker is usually on the top anyway.

[lookalikehuuh]

Originally Posted by lordnikon

The sticker is usually on the top anyway.

I haven't seen any stickers on the top unless they are aftermarket units. The Valeo and Bosch units I have seen on all the E90s I have worked on have always been on the backside of them.

I haven't work on any late model E90s though, so maybe for those units?

[lordnikon]

Originally Posted by lookalikehuuh

I haven't seen any stickers on the top unless they are aftermarket units. The Valeo and Bosch units I have seen on all the E90s I have worked on have always been on the backside of them.

I haven't work on any late model E90s though, so maybe for those units?

Maybe. My OE Valeo alternator has a sticker near the top. Same for Bosch reman ones.

[lowrydr310]

Originally Posted by lordnikon

Maybe. My OE Valeo alternator has a sticker near the top. Same for Bosch reman ones.

Yep, my Bosch remanufactured alternator has a big sticker right on top of the back plastic piece.

[tlow98]

Originally Posted by lookalikehuuh

I think the mirror is probably the easiest method.

I personally use one of these mirrors with lights on them:

https://www.amazon.com/Telescoping-S...1zcF9hdGY&th=1

A mirror with a light attached, I'll be damned. I've been balancing the flashlight in my mouth like a caveman.

Tool purchase commenced... ty!

[The Nightman]

Originally Posted by lookalikehuuh

As far as replaceing the voltage regulator on its own... I don't know if the Bosch unit will be fully compatible with the Denso alternator, but if you have no other choice, it might be worth giving it a shot. In fact a new voltage regulator might just fix your old alternator as its a very common reason on why alternators stop working... the brushes just wear out.

Confirm from your original alternator, but it should be: https://www.fcpeuro.com/products/bmw...sch-f00m346089

Beat me to it. Always try to replace the voltage regulator first!

I've also revived old ABS motor pumps by replacing their brushes. "L5-5H" copper graphite brushes seem to work well for those applications.