Hey Guys,
I used a standard Bosch 4 wire relay - nothing special.
The INT lead is what triggers the relay by giving it a ground path. DO NOT hook a 12V source to this wire directly. The ECU is only expecting a 120 - 160 mA power source from this wire.
The MTT wire either checks to ensure the relay is working properly, or is a test lead to check resistance across the pump.
M+ and M- are testing that the pump is working properly - (voltage drop).
Lev is grounded to simulate a properly functioning level sensor / switch.
For me, the light does not come on when the car is started - just when tb opens. It turns off after the car is idle for 30 seconds.
I helped wire up the 205 IC pump and level sensor on a guys 1st gen MR2 with a 205 swap. Everything was wired up, and he was still getting code 54. He replaced the ECU with another 205 ECU and it worked fine.