My 95 355 bypass valve does not open. I have isolated it to electrical signal, but now I am stuck. It stands to reason that a signal from one of the two ECUs (2.7 Bosch) has to send a signal to the control valve that opens the vacuum to the bypass valve. On the 5.2 ECU, there is such a signal at pin 63. On the 2.7 ECUs, I have looked on the official Ferrari schematics and found no such signal from either bank 1 or bank 2 ECU. Does anyone know which pin from which ECU controls the bypass valve relay switch?
Found it. Pin 21, bank 2 is the signal controlling the bypass valve. Pin 21, bank 1 is the signal controlling the secondary air pump. Both circuits are powered by a K relay. My relay is dead.
In the footwell, a K relay, with dual circuits one feeding the bypass valve and the other feeding the secondary air pump
