A6 2.4 runs for 10 seconds and then crashes.

I have an A6 that runs for about 10 seconds, then diesels, and the cooling fan starts running.

After that, I can no longer connect to the engine control unit with VCDS, Gateway Motor 0.

I measured the power supply to terminal 30 (B3, B4, B6) on the control unit.
Terminal 30 to B92 (from the fuse box)
Terminal 15 to B87, voltage present everywhere
If it stands for longer, I can reconnect to the engine control unit.
The car then starts, runs for a few seconds, and diesels again.

I connected a lamp to terminal B3, but the engine is dead.
This has happened twice, and then the fuel pump relay started switching. The engine no longer started.

I shorted the fuel pump relay, but still no engine running.
The lamp on B3 is still lit, but after several attempts, I can no longer connect to the engine control unit, and in the gateway, I have a 0 for the engine, the lamp on B3 is no longer lit, but on terminals B92 and B87, it is. The cooling fan is running.

I also shorted the power supply relay and the fuel pump relay, but it doesn't help.

So, the engine control unit no longer activates the power supply relay for terminal 30 after a certain time.

My question: Is it sufficient for the control unit to have power at terminals B92 (terminal 30) and B87 (terminal 15), and of course the three ground connections (B1, B2, B4), to then supply power to the power supply relay (terminal 30)?

I also can't connect to the immobilizer control unit 25, but as far as I remember, it is integrated in the 05 model.

Here are some MBW:

Address 05: Access/Start Control (4F0 910 852 )

15:18:21 Block 007: Voltages
12.960 V Supply Voltage
0.288 V Output Voltage to activate Term. 15
[color=red]This will never be displayed here[/color]
0.288 V Output Voltage to activate Term. 75X - I have 10.8V when starting
0.000 V Output Voltage to activate Term. 50 - I have 10.8V when starting

15:20:08 Block 008: Ignition Switch (E415)

unbetätigt Locked 1
betätigt Locked 2
betätigt Unlocked

15:21:29 Block 009
unbetätigt Switch Motor 1 Relay 1 Term. 15
betätigt Switch Motor 2 Relay 2 Term. 15
ein K15/P Wire from Ignition Sw. (E415)
[color=red]When ignition is off, set to off[/color]
off K15/S Wire from Ignition Sw. (E415) [color=red]Always off[/color]
Should the MBW 007/7 have a battery voltage when the ignition is on? And what about MBW 009/4?

Address 09: Central Electrical (4F0 910 279 K)

15:25:11 Block 015: Connection Status
on Terminal 15
on Terminal X
off Terminal 50
N/A

Address 4F: Central Electrical II (4F0 910 280 )

15:26:13 Block 005: Power Supply
on Terminal 15 Status
on Terminal X Status
0.1 Dynamic battery control shutdown level
0.1 Static battery control shutdown level

I could now measure the CAN connections with an oscilloscope. But I only have an old analog one.

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