Use this Development request to investigate an existing application after Setup.
An external I2C sensor reports that its bus is ready, but register reads return -EIO.
Use trusted Nordic sources for the project's exact nRF Connect SDK version and board target to investigate the error.
Check the devicetree binding, pin control, device address, controller selection, relevant Kconfig symbols, transaction-debugging options, and known SDK issues.
Explain the evidence and recommended diagnostic steps before changing files.
This symptom-driven request gives knowledge search enough context to distinguish several potential causes. These causes include wiring, devicetree, configuration, driver, and SDK version differences.