We were called to diagnose a Hino 700 equipped with the E13C-UN engine, which had symptoms of poor performance going into limp mode when RPM reached 2000.
As always, we begin by first checking for fault codes, in this case we used Hino's oem tool DX2, which resulted in a plethora of mainly past fault codes.
The past fault codes were cleared and the vehicle was tested again for fault codes by revving up to 2000 RPM and fault codes relating to the Turbo/VNT actuator were present, since Hino's oem tool allows for actuation and live data inspection, we actuated the VNT by letting the truck at ignition on and it was found that the VNT actuator was not responding.
Wiring between the Actuator, the actuator controller, and the ECU were checked which were all solid and no defects were found, it was found that the actuator was defective and caused the controller to also malfunction, replacement actuator and controller were ordered and solved the problem.