Z4 E86 coupe 2007/8 noise

[V-2f0ue]

Hi,

The battery is continuously draining at 1.5A when everything is turned off. Under the rear possibly to the nearside I can hear a low level hum/whirring sound that disappears when battery disconnected. I haven't had it up on the ramp yet but would welcome any ideas what I should be looking at/for.

Also, the battery went flat, so the car is now in transport mode. That's another problem, no aircon.

[InitialDave]

Fuel pump?

[V-2f0ue]

That was my thought but why would it be running when the ignition is off and key removed, doors closed and locked??

[Wills2]

Not experienced that on mine, but could be the RDC control unit according to Google that is located at the rear they can fail and continue to "work" draining the battery causing that noise.

[InitialDave]

V-2f0ue said:

That was my thought but why would it be running when the ignition is off and key removed, doors closed and locked??

A lot of cars prime the fuel pump on unlocking, so my thought was it could be stuck in a cycle of doing that constantly for some reason.

[Mr Tidy]

I don't have any specific ideas but imagine you need to start by checking for any fault codes in the OBD.

Transport Mode is a PITA. It was supposed to be deleted as part of the PDI but so many dealers seem to just disable it. As well as no A/C you'll have no heated rear screen. I think it can be deleted using INPA or ISTA.

[V-2f0ue]

Agreed re transport mode, a real PITA and stealers are not willing to do it for a vehicle without charging the earth for what should have been done.

I can't get INPA or ISTA running as we are Mac only here with only one Windows 11 and I believe they dont run on W 11.

And my OBD tool doesn't connect to the car for some reason. May point to a bigger problem I suppose. But the car runs great.

P

[V-2f0ue]

Hi

More of a mystery now.

I pulled all fuses out that were indicated as live when battery connected but key out and car locked except the one that is for the alarm immobiliser because it shreeks if that one is out . And the battery drain was still at >1amp.

The noise was still there. It seems to be from the area in front of the tank but ahead of the diff/suspension area. I cant get it on a hoist until next week so it is driving me mad not being able to trace it.

Anyone in the south east able to disable the transport mode sometime?

P

[Mr Tidy]

It might be worth asking that question on z4forum as quite a few guys on there have the right software.

In fact it might be worth asking you original question on there too!