DTC P1889-18: Oil Pressure Pump Performance - Circuit current below threshold: Action

Refer to the relevant service information and check the transfer case fluid level. Rectify any leaks as necessary. Drain and refill the transfer case with the specified grade and volume of fluid
Refer to the appropriate system wiring diagrams and check the transfer case fluid pump circuit for open circuit, high resistance. Repair the wiring harness or install a new transfer case fluid pump as necessary
Using the Jaguar Land Rover approved diagnostic equipment, clear the DTCs and perform routine - On Demand Self Test. If the fault persists, install a new transfer case control module