Hello John

Looking at the wiring diagram sensor 1 and 2 shares the same fuel pump relay live so this should rule out supply at s1 and s2 join

I would have a look at the ECU switched ground circuit with a scope during warm up to see if the circuit on and off time changes with temp
maybe also a good time to give the wiring wiggle test

look at the live data to see how quickly the sensor starts out putting a value and system goes closed loop (just in case the code is system logic not seeing CL quick enough)


HTH
Terry