2006 Lexus GX470.
Looking for advice here. I had to remove my intake to do work under the intake, also installed new injectors and plugs. Had the batt disco'd for days. Put everything back and the ECU will not ground the C/OPN relay coil so the C/OPN relay can supply +V to fuel pump relay. Everything else seems ok (voltage is there at C/OPN relay, pump works, no DTC's, all fuses are good, etc etc). The ECU pin that controls the C/OPN relay coil is the "FC" pin on ECU (common collector transistor most likely). From the wiring diagrams the "FC" wire between ECU and C/OPN relay appears to be a homerun wire, which makes sense from a safety perspective.
I found this post in this forum. Dealer told him "some connectors". What connectors could it be? Could it also be the immobilizer? Not much info about what the immobilizer does. Does it serve as a security feature and safety feature if say an airbag is deployed, cutting off the C/OPN relay?
http://forums.pelicanparts.com/off-topic-discussions/646599-mechanics-need-help-understanding-toyota-fuel-pump-problem.html