From Ross-Tech Wiki
16989/P0605/001541 - Internal Control Module: ROM Error
- Malfunction Indicator Light (MIL) ON
- Control Module faulty
- Internal Fault in Control Module/Processor
- Check/Replace Control Module
- Fault Codes like this can usually not be repaired since they are stored after the Control Module did not pass it's internal Self Test. Even though the official Repair Manuals suggest replacing the Control Module in such a case, there may be specialized Companies repairing Modules like this.