Upon first use or after an update of its firmware, the IIDTool will scan the communication buses and note which ECUs are responding. The resulting list is stored in the IIDTool memory.

This process needs to be performed with ignition ON or engine running. Failure to do so will result in missing ECUs in the tool list. 

To avoid this, always connect the tool with ignition ON or engine running.

To fix this,

-Start the car

-Connect the tool

-Menu–IIDTool Config–Find ECUs

If a new ECU is installed or removed from the vehicle, the Find ECU function shall be used to add or remove the ECU from the list.