Diagnostic Aids

WARNING: This page is about a different car, the 2003 Ford Pickup, 2003 Ford F550 Super Duty, 2003 Ford F450 Super Duty, 2003 Ford Excursion, and 2003 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

The Variable Geometry Turbocharger (VGT) is controlled by the Powertrain Control Module (PCM). The PCM utilizes an Exhaust Pressure (EP) sensor to monitor the pressure and adjust the VGT solenoid duty cycle. The VGT solenoid receives a Pulse Width Modulated (PWM) signal from the PCM that controls the solenoid on/off time. The VGT solenoid directs oil to a piston within the actuator housing. The direction of oil flow to the piston increases or decreases the exhaust pressure. The VGT solenoid control is based on input sensors. The input sensors are used to calculate engine speed, desired fuel quantity, altitude, and exhaust pressure. The amount of voltage the sensor deviates from a calculated reference value (sensor bias) may cause a commanded versus actual pressure calculation error.

The PCM monitors the exhaust pressure. A DTC is set when the difference between the commanded and the actual exhaust pressure is not within the calibrated limits.