P2033-00 EXHAUST GAS TEMP SENSOR CIRCUIT HIGH BANK1 SENSOR2

Morning all
Transit has following fault code. This has had a previous repair to sensor wireing and looks like good sensor. Replace sensor with known good one and made good wiring.
Code comes back after long road test.
Live data 5v to all sensors and exhaust gas temp 1000oC.
My first though is it must have a open circuit to ECU checked all wires back to ECU all okay. Fitted variable resistor to senor wires and volts fluctuates but temp stay the same.
I have now run out of ideas can anyone help ?
Cheers
Mark