Problems, no diagnosis with a Lupo 1.7 SDI AKU, built in 2003.

Hello everyone,

I have a problem with a vehicle that many people have already had issues with.

LUPO SDI Engine Code AKU

Neither the engine control unit (ECU) nor the immobilizer control unit can be diagnosed. Logically, the vehicle does not start.


It has come to light that the ECU cannot be connected to pin 37 (15).

"Does it light up the engine control lamp and indicator lights directly there? If not, diagnosis is negative."

The error lies in the area of relay 405 (Sog J491, Power cutoff, Crash).

This is controlled by the airbag control unit.

Has anyone here had any problems?

My relay is constantly pulling, which has interrupted the circuit to the ECU pin 37. But why can't it be read out if this is bypassed by directly applying + to the circuit?

Will this device (Relais 405) cause more interruptions here?

Why is the start-stop system (External STG not in the tachometer) also not diagnosable?

Who has tips here?

Take the schematic. Then, from the WFS box, ring the bell to the MSG. The WFS box also has a Kl 30 and a Kl 15. And all of them are connected to the same network.