Complete Electrical Malfunction in BMW F31 While in Motion - Has Anyone Encountered a Similar Issue?

[TheCreakyChair]

Greetings everyone,

I seek guidance from anyone who may have encountered a similar situation or can provide direction. I possess a 2013 BMW F31 that has manifested an unusual and significant electrical problem, which I am currently endeavouring to resolve.


Several months ago, my nephew was operating the vehicle at approximately 60 mph when it abruptly ceased functioning – the engine stalled instantaneously, the dashboard went entirely dark, and there were no indications from the iDrive or any lights. It failed to initiate on the roadside as well, exhibiting no response.

Subsequent developments are as follows:

Battery replacement executed → no improvement
A buddy installed a new starter motor, as initially thought; however, the car started just once and operated very roughly, with rattling and instability, as if it were lacking voltage.
Subsequent to that solitary initiation, it reverted immediately to a state of complete inactivity.
A mobile mechanic just installed a fully charged battery; yet, there is still no answer.
The iDrive would momentarily display the BMW emblem before shutting down again.
The hazard button began to flash autonomously and could not be deactivated.
The central locking function operated solely with the physical key.
Diagnostics revealed several "low voltage" errors across the majority of modules.
The car remains unresponsive to a jump start, even when using heavy-duty cables from a vehicle.


As of today, the symptoms have altered once more:

The hazard button has ceased to flash.
The iDrive is completely nonfunctional at present.
There is entirely no inner power, no flicker, nothing - it is more "dead" than it has ever been.


The vehicle has transitioned from intermittent low voltage issues to a total lack of electrical power.

Considering all factors, I am inclined to conclude that the issue pertains to a significant power distribution failure, rather than an immobiliser/CAS malfunction, a starting problem, or a battery deficiency. The probable suspects appear to be:

Failure of the main engine to chassis ground strap (a prevalent issue in F-series vehicles)
The primary battery wire from the trunk to the front jump point is exhibiting significant resistance or experiencing internal failure.
Damaged fusible link or BST (battery safety terminal)
The FEM is losing its B+ or ground supply, rather than the FEM itself being defective.


An independent mobile specialist for BMW/Mini is scheduled to assess the issue. However, prior to his arrival, I would want to enquire: Has anyone experienced a total power loss in an F30/F31/F32 while in motion, followed by an inability to restart or accept a jump start thereafter?

What was the cause, if that is the case?

Any insights from those who have seen analogous issues on the F-series platform would be greatly valued. I seek to refrain from indiscriminately spending on arbitrary components and would appreciate insights on what has effectively resolved the issue for others.

Thank you in advance!

[EchoTrail]

To experience a complete loss of electrical power, I would begin by inspecting the battery. Transfer locations where battery power traverses the body to the primary cables below; the grounding point from the negative terminal warrants inspection.

[TheCreakyChair]

Greetings,

When a charged battery is attached, voltage is present under the hood, indicating that the main cable is intact. Based on my readings, the complete loss of power may have been due to low voltage to the FEM. I believe there will be two or three issues instead than just one. I anticipate acquiring more information tomorrow, although it would not astonish me if I do not.

[Startle]

There appears to be an issue with the primary connection to the main fuse panel, possibly related to the B+ terminal, however I am uncertain regarding your vehicle.
I believe it pertains to older models.

[NotePapa]

The e9x series experienced a battery cable defect; I had mine replaced in an e92 335d, accompanied by a recall letter. Therefore, I presume the issue has been resolved in the f series, as I have not encountered reports of it. Perhaps consult Jason at BWChiptune; you can find them online.