LMP91000: LMP91000

Hello!
There was a following problem.
I want to use LMP91000 as the transimedance amplifier of an oxygen sensor. I enter all the settings in accordance with the datasheet p.19. LMP91000 is working correctly, the voltage will match the current at the input. But between the pins of CE-PE and WE measure the current from 1 to 6 μA. What could be the reason for such a large bias current? Config = 0x07; 0x40; 0x03;