2016 X5 40e hybrid alternator not engaging

[Freude_am_fahren]

Hey,
I have a 2016 X5 40e. The car won't start without jump box. The instruments on the cluster just flicker. It starts with a jump box. I can see the starter/hybrid alternator spinning when it starts. After that the belt from the hybrid alternator to the crankshaft pulley does not turn.
The blue hyrid battery symbol on the cluster showed one bar. After I let the car run for a while it showed two bars. How is that possible if the alternator belt is not turning? Where does the car take its power to run from?
It shows voltage of 12 V battery system when running is at 14.97 V. Is there another alternator in the car?

When I plug in the charger to charge the hybrid battery nothing happens, battery is not charging and no light visible at the charging port.

I deleted the codes the car had and these ones came back/are still there:
CD8F04 starter unit, charging controller for auxiliary battery: no LIN message
CDA520 no message (status, pressurised fuel tank, 0x2E7) receiver DME, trnsnitter TFE
CDA66D message (status of OBD diagnosis 6 drive train, 0x19E) missing receiver DME, transmitter EGS

Or is this thing that is connected with a belt to the crankshaft pulley just the starter and it is not an alternator? Maybe somebody can explain to me how the car works XD

thanks

[corduroy]

How old are the 12v batteries in your 40e? There are 2, 12v batteries. These will start throwing codes, seemingly random codes, when the 12v batteries are dying. Something to do with voltage drops across the system and only some modules reporting errors. The 12v system might show 14.97 V but... they just do.

[Clifton]

Agree with corduroy - Sounds like old 12v batteries. As mine reached 5 years old and cold weather set it (Nov/Dec), they became unreliable and I started seeing all kinds of strange behavior (iDrive, gauges). These were on top if it being slow to start.

Additionally, that last code "CDA66D" was something very similar that mine persistently threw even after battery change. It eventually flushed itself after driving for a few weeks.

[COSPILOT]

Not suggesting I have answers, as I'm new to X5 ownership. That said I've been a Land Rover owner since 2002 and any drop in voltage will create a ton of issues. Battery replacement has worked every single time. Land Rover still has a lot of BMW in it.

[Freude_am_fahren]

Originally Posted by corduroy

There are 2, 12v batteries.

Yeah, I know about both of them and will replace them and see what will happen then.

Does anybody know how the charging system works? Is the thing in the front that is connected with the belt to the crankshaft pulley just a starter? Where is the alternator?

[corduroy]

I've been reading a bit and I'll try my best here, lol. But by no means am I an expert.

It looks like there is NOT an alternator for the 40e. There is a transformer that charges the 12v batteries (I've noticed that the batteries drain more if you have it on eco mode as compared to sport and comfort, probably because there's minimal regen). If the 12v system is low/not working, the EME (the computer that controls the High-Voltage system) can no longer regulate the flow of electricity between the HV battery and the motor (and/or external sources, possibly a charger).

This thread is really informative but might not apply to you: https://www.justanswer.com/bmw/bpx6s...-codes-no.html

There are a couple fuses you can check (https://fusecheck.com/bmw/bmw-x5-f15...8-fuse-diagram). It looks like Fuse 41 under the glovebox (LHD) and 615 (not sure where this one is). If you have ISTA, that can tell you exactly what's going on.

For a 2016, those 12v batteries are old. That should definitely be the first thing you do. I've read about the EME failing on the i3 and i8. I'm not sure if that's a thing with the 40e (I haven't read anything about that on the 40e). But the last thing you want is for that EME to be damaged, otherwise you'll need a replacement or a shop that can try reflashing it.

[Freude_am_fahren]

Originally Posted by corduroy

It looks like there is NOT an alternator for the 40e. There is a transformer that charges the 12v batteries

Okay, how does the car convert the kinetic energy/rotating motion of the engine into electric energy/electric power? How does the car charge the hybrid battery?
How does the car supply all its components with electricity during a five hour drive? There must be some kind of alternator or device that turns motion into electricity.

[corduroy]

Originally Posted by Freude_am_fahren

Okay, how does the car convert the kinetic energy/rotating motion of the engine into electric energy/electric power? How does the car charge the hybrid battery?
How does the car supply all its components with electricity during a five hour drive? There must be some kind of alternator or device that turns motion into electricity.

Like I said, I'm learning this as I'm looking.
https://www.bimmerfest.com/threads/l...nator.1415685/

That says that it's a starter/alternator. So, it doesn't seem like a typical alternator found in traditional ICE vehicles.

https://www.bmwpartsdeal.com/parts-l...m/starter.html
Here's an image of it.

https://www.youtube.com/watch?v=eo9r2dYOSBY

As far as regen goes, that video says that the e-motor acts as a generator for recharging the HV battery when decelerating the car.

I don't have time to read it, but this seems to explain BMW's system a bit. However, it's more on the powertrain and not too much with electrical.
https://x-engineer.org/bmw-phev-powe...-architecture/

Good luck.

[Freude_am_fahren]

The starter looks like a conventional starter with a plunger. Why does it have the plunger unit when it is always connected to the crankshaft pulley with a belt? The crankshaft pulley seems to have a clutch that might only engage when the starter motor is active.
From how it looks I don't think that thing is able to act as a generator and to generate electricity.

That's how the starter belt looks in my car.

And that is a picture I found online.

I read through the link about BMW hybrid vehicles and about the 740e. I now think that the electric power in the X5 40e comes from the electric motor (inside transmission) which can also act as a generator/alternator. So powerflow to the 12 V battery is: gas engine runs > turns electric motor in generator mode > charges hybrid battery > charges 12 V battery through transformer

[Freude_am_fahren]

Okay, I dropped two new batteries in it, registered them, everything is fine now lol. The car is charging with the cable, CEL is gone, it all works as it should, I am happy.

[corduroy]

Originally Posted by Freude_am_fahren

Okay, I dropped two new batteries in it, registered them, everything is fine now lol. The car is charging with the cable, CEL is gone, it all works as it should, I am happy.

LOL, nice!

It's amazing with how BMW can have so many things can go wrong in these cars when the 12v batteries go low (despite showing a good voltage). And then just plopping in new batteries makes it all go away, lol.

[Clifton]

Originally Posted by corduroy

It's amazing with how BMW can have so many things can go wrong in these cars when the 12v batteries go low (despite showing a good voltage).

Very true - my understanding is that BMWs have always been hyper sensitive to voltage. I remember my E36 required special (brass?) bulbs for the taillights. Of course the dealer wanted crazy prices and many Auto parts store offered an affordable alternative. Unfortunately, using those cheaper bulbs often caused "check control" issues via the on-board computer.

I've never had an issue, but supposedly even soldering wires is known to cause increased resistance, which the car doesn't like, leading to electrical gremlins.

[chumbedi]

Had similar problem with X5 40e, after using a CTEK charge, problem was solved.
Either 12V battery is too old, errors can occur if you drive short distances in economy mode (low regen of high voltage battery/ no recharge of 12Volt battery)

[bmwiuser]

We repair BMW F15 EME (Hybrid Invertor). You can contact us on tel or WhatsApp: +380992814817
Our website: Repair EME

[FREE100KSECRET]

I am going through same issues now as the main 12VDC died and killed the vehicle and had to have it towed home. Replaced and registered battery and checked the Aux 12VDC and it was reading 14.93 V even without motor running which seemed strange to me. I understand voltage sensitivity issue but does too high a voltage shut down modules.

So Hybrid battery charges fully to 18 miles, and I understand there are two starters for this 40E, one is conventional in front of motor which drives with cog belt and then one in transmission which is also where alternator function comes from. So the cog starter is standard like most, except for drive cog belt.

My issue is DME and EME permanent fault and all low voltage faults were removed and only a few remain indicating a short somewhere. Does that mean an open wire connection or a short to ground, and where would this be located is the real question. Anyone have any tips where to look next. Could high 14.93V on aux battery which drives the standard starter be the problem? Totally lost on this Hybrid.

Thanks,