E61 Tailgate remote release/power assist
 

Howdy folks!

I've got a problem with my tailgate where it won't open by the remote.
The hydraulics work with the button on the inside of the tailgate and will close it fine. The remote works with locking and unlocking. But I cannot open or close the tailgate using the keyfob.
Using the switch built into the tailgate will unlatch the tailgate but not run the hydraulics, so when using that I need to yank the switch and get it to unlatch then lift it manually.
I'm 99.99% certain that there is no issue in the tailgate wiring as I've done a full replacement on the entire rear wiring harness and everything else works seamlessly.
I've been told there's some way to 'recalibrate' the system but I haven't been able to find any documentation on anything like that.

Thanks!

Have you tried another remote? Also, read the BMW DTC codes.

That's what I'm thinking. Does the remote activate the lock mechanism ? If not I would try another remote first before going further.

I'm kind of confused by the OP's description. It all lines up with a bad fob (probably tailgate switch itself on the fob), but then he said: "Using the switch built into the tailgate will unlatch the tailgate but not run the hydraulics". But earlier he said "The hydraulics work with the button on the inside of the tailgate and will close it fine".

I saw that too but focused on the fob issue since I think that was his main complaint. Maybe the OP can shed more light on what he meant by that because it definitely was confusing.

Thanks for the feedback everyone, I went and re-checked all the symptoms and it seems like my memory failed me a few days ago; the actual symptoms are as follows.
When the trunk is closed and the car is unlocked, the keyfob & switch on the tailgate (the one just above the license plate, not the one on the glass) will both trigger the lock and unlock the tailgate, however in neither case will the hydraulics take over and lift the tailgate up. I have to manually lift the tailgate up. Once it has been lifted up, it will stay in position.
When the trunk is open, I can push the button on the inside of the tailgate to close it using the hydraulics without issue.

I hope this all makes sense; thanks again for the help!

Sounds like a garden variety low-fluid situation to me. When enough hydraulic fluid leaks out over the (many) years, the tailgate gets sluggish, and raising it becomes slower, more intermittent. It's happy to go down more than up.

Happily, there's a (fairly) easy solution...

Already did this exact fix; that's why it's even able to hold itself up and go down. It's not the pump. Or at least, I'm 99% sure it's not the pump.

Interesting. Does it feel like the pump is trying to lift the tailgate (as in, you can supply a little extra umph by hand and the tailgate will lift)?

And there's the other strut (which I suppose is a typical gas-filled "lift strut" like on most lesser cars). Have you tested it to see if it's still got the appropriate amount of push?

Nope. The pump doesn't do anything other than hold the tailgate in place. Doesn't sound or feel like it's applying any extra force.

I haven't checked the other strut, but before I refilled the pump, the tailgate would go down quite slowly as if the gas strut was doing whatever it could to keep it upright so I'd assume it's all good.