Terminal 30 at the engine control unit (ECU) - Seat Altea

Hi,

I have a SEAT Altea 1.9 PD in the workshop where there is no voltage reaching terminal 30 of the engine control unit (ECU). Terminal 15, on the other hand, is working correctly.

Does anyone know how this is exactly wired? Besides the battery, there's a small fuse box, and then another one located on the left side under the steering wheel, near the central electrical system.
I'm excluding the relay (109, 219, etc.) because it's connected to the constant positive terminal (terminal 30).

Greetings.
John.

Hello Johannes,

The engine control unit is usually mounted on a fuse box, possibly with other components attached, and located where all the other fuses are.
Don't ask me which one it is for the Altea.

Best regards, Rainer.

Hi,

Terminal 30 for the engine control unit (ECU) is switched via a relay in the fuse box next to the battery. That's where the fault was located.


Thank you for your help!

Huh? Terminal 30 isn't terminal 30 when it's activated...

It's been a classic for decades at Volkswagen.

The relays are developing cold solder joints, which causes the power supply to the microcontroller (MCU) to fail or the entire circuit to malfunction intermittently.