How do you fix code p1698?

Code P1698 typically indicates a problem with the communication between the engine control module (ECM) and the transmission control module (TCM) in vehicles. To fix this issue, first, inspect the wiring and connectors for damage or corrosion. Ensure all relevant fuses are intact and check for any other diagnostic trouble codes (DTCs) that might provide additional context. If necessary, reprogram or replace the ECM or TCM based on the manufacturer's guidelines.