Aux 5 giving 12 volts

EMU BLACK / CLASSIC
1

Hello

My car was sitting for about 6 months because of engine problems. Now that I have it running again the boost control didn´t work at all. I started measuring and found that the AUX 5 (EMU Black) I have it wired to shows 12v. Even when I removed the wire from the ECU plug, it still showed 12v at ECU pin, even with the solenoid plug disconnected. There was no continuity to any 12v source. Voltage dissappeared when ignition was turned off, but the pin didn´t ground then either.

The solenoid in question is 3 port Mac. It was also stuck, but that doesn´t explain the voltage. Now that I cleaned the valve, it works as it should and measures sensible resistance. Boost control works as it should now that I changed the output to AUX 2. Battery was removed when the car was sitting.

Does anybody have any idea of what might be behind this? I still have warranty left, but don´t feel like sending the ECU away as the car works now. Especially as I´m not sure if it is faulty in the first place.

2

Ecu aux have internal pullups. That’s your reason for12v . Use test outputs function to check if sending ground when activated

3

That makes sense. Are output pins grounded when not assigned to anything? I´ll have to do some more measuring tomorrow as I didn´t think to measure it during output test, or measure the AUX 2 when it was assigned. Thank you!