[green grass]

Bone stock 2013 F30 328xi, N26. No mods, 116k, thereabouts (bought ~10k ago)

Symptoms

Recently it's been giving me the "Drivetrain malfunction, drive moderately" error occasionally on startup, but behaves perfectly normally. Error only appears on startup, and usually clears spontaneously after a few miles. The error never appeared with stop/start (although I've disabled that as a caution) and has never appeared while the car is driving. The following codes appear:

• 1B5202 - Terminal 15N_1: no voltage
• 1B5302 - Terminal 15N_2: no voltage
• 1B5402 - Terminal 15N_3: no voltage
• 130002 - VANOS solenoid valve inlet, control: short circuit to ground
• 130202 - VANOS solenoid valve outlet, control: short circuit to ground
• 122002 - Diverter valve, control: short circuit to ground
• 1C0202 - Engine oil pressure control valve, control: short circuit to ground
• 120408 - Boost pressure control: shut down as a follow-up reaction
• 12B102 - Lambda probe heating after catalytic converter, control, short circuit to ground
• 102A01 - Air mass meter, signal:electrical fault
• 1D2402 - Map thermostat, control: short circuit to ground

Battery is new.

Speculative diagnosis

In any other car, I would guess this is a starter relay fault. Terminal 15N is post-start ignition on, and my guess is that the starter might be drawing too much power, causing the DME to brown out, causing all the above random shorts.

The no other system (FEM, etc, etc) shows any faults on startup, so I might also suspect something wrong the the DME cabling.

From what I can tell, the F30 doesn't have a removable starter relay though. I would either need to replace the front power distribution box, rear power distribution box, or the power distribution module on the driver's side.

Mitigating actions

I've been mitigating the problem by pressing start without the foot on the brake, letting the computers boot up, and then starting the engine. The theory behind this is that whatever the problem is, it's made worse by having having every system demand power at once on startup, and this staggered start up procedure with smooth out the power demand.

I've never had the error pop up when doing this, but absence of evidence is not evidence of absence.

Given that I suspected DME electronics, I also popped off the engine cover and ensured that the connections to the ECU are not loose. They looked fine.

Cure?

I'd like to actually fix this problem though. As above, I suspect the power distribution boxes, power distribution module, and perhaps ECU wiring harness, in that order.

I hate throwing parts at an intermittent fault. Half the time it makes things worse

Anyone have an idea what might be going on?

Thanks

[drummajorc]

were you ever able to resolve this? running into the exact same bunch of codes along with not being able to start the car at all, car just cranks but does not start. Already attempted replacing IVM and IVM cable after finding a break in that cable.