Mitsubishi L200 SCV P0089 Fault Code: Persistent Issue After Injector and Fuel Pump Replacement

I recently encountered a P0089 fault code on my Mitsubishi L200 SCV, even after replacing both the fuel injectors and the high-pressure fuel pump. I've thoroughly inspected all inlet fuel components—including the fuel filter and fuel tank—and everything appears to be in good condition. The engine starts smoothly without any issues, but within one minute of operation, the P0089 code triggers and the yellow warning light illuminates. Using my OBD2 scanner, I observed that the common rail pressure remains stable at approximately 300 bar throughout operation. The SCV (Supply Control Valve) duty cycle consistently reads 100% and does not change, even when engine RPM increases—this behavior is highly unusual. When the P0089 code activates, the SCV duty cycle drops immediately to around 15%, yet there's no corresponding change in SCV voltage. I measured both the voltage level and waveform using an oscilloscope, and the readings remain constant throughout engine operation: a steady 4.2V with a consistent wave shape—indicating no variation during start-up or runtime. The resistance measurement across the SCV shows a value of approximately 5.6 ohms. These findings strongly suggest a potential failure in the SCV itself. However, given that replacement parts are expensive in my country, I'm seeking a second opinion from other Mitsubishi L200 owners and technicians before proceeding with a part swap. Any insights or experiences with similar P0089 issues after fuel system repairs would be greatly appreciated.