Theory Of Operation

The Fuel Quantity Solenoid (FQS) is an electronically controlled solenoid valve. The Powertrain Control Module (PCM) provides a Pulse-Width Modulated (PWM) driver circuit and ground circuit to the FQS. The PCM varies the current to this valve to provide the correct fuel flow to the High Pressure Pump based on operating conditions. The FQS is a normally open valve. High circuit resistance may cause fuel pressure to be higher than commanded at light loads. Although this is primarily an electrical diagnostic check, fuel supply issues and high pressure leaks can cause the PCM to force the FQS into a region where this fault code becomes active. During this time the customer may experience a torque reduction.