What is causing error P0689 on the Isuzu?

Question

The Isuzu KB 250 d-teq had contaminated fuel with water, the injectors were changed, solenoid, crankshaft sensors, raves sensor, and airflow sensors were also changed. The vehicles has had vibrations on and off, and now it is giving us an error code of P0689, what could be the problem? Engibe controls ignition relay control circuit, Faulty ignition switch, ECM malfunction and faulty elay were checked and they seem to be working.

What could be giving this error of P0689?