Quote Originally Posted by BCX View Post
pin 1 initialises any ecu that is on the k-line bus (TCU, AYC, EFI, ABS, ACD)

As part of the 5-baud init, you send a unique address. this specifies what module will communicate.
Exactly, so holding it to GND would prevent initialising any other ECU, it's just a fluke that the EFI ECU responds if this is permanently grounded.

Quote Originally Posted by BCX View Post
as for reflashing, reflash connector has a dedicated pin for each module that can be reflashed. In our vr4, this internally joins to the flmcr pin of the H8 to provide it with a voltage to burn the rom (remove read only protection) and gets the rom to boot the flash kernel.
Don't suppose you can confirm if the voltage applied to that pin is the same as battery voltage (+12V to +14V) or if it needs to be the higher band of +16V to +18V?