The vehicle intermittently goes into limp mode, with the check engine light on.

The vehicle was found to intermittently lose power and enter limp mode. Fault code P1251 for the step motor of the turbocharger control circuit (intermittent) was stored and would reappear after approximately 30–40 minutes of driving. A new turbocharger assembly, including the stepper motor, had already been fitted, but the problem persisted.