F56/57 fuel gauge circuit

[peaktorque]

I've recently purchased a cheap 2011 Cooper S ragtop, fuel gauge is dead!

I've accessed the 'secret menu' and read the tank levels from each sender. The LH is working, but the RH side is showing as open circuit, I thought it was a dodgy tank sender, but if i connect the RH terminals to the LH tank sender, it still reads as open circuit. If i connect the LH wires, to the RH sender, it shows the correct fuel level, so i can rule the sender out as faulty.

I've checked the earths and they're fine, checking the voltage at each level sensor terminals, they both read 0.4v (which seems low, but the LH is displaying correctly on the dash read out). It seems like the voltage isn't being seen by the ECU?

Any ideas?

Thanks