Some 2011-2012 Ford F-150 vehicles equipped with a 3.5L GTDI (gasoline turbocharged direct injection) engine and built on or before 5/24/2012 may exhibit an intermittent MIL with DTC P0234.
Remove the engine cover, and remove the turbocharger vacuum regulator solenoid that’s mounted on the right side of the upper intake manifold. Remove the vacuum tee and vacuum supply hose connecting the turbocharger vacuum regulator solenoid to the upper intake manifold.
Disconnect the vacuum supply hose from the vacuum tee. Ensure that the vacuum supply hose is clear of any internal contamination. Trim any exposed plastic material flashing off of the vacuum tee using a razor blade. Install the vacuum tee and vacuum supply hose.
Install a new turbocharger vacuum regulator solenoid. Reprogram the PCM to the latest calibration using IDS release 83.01 or higher. Calibration files may be obtained from www.motorcraft.com.
Advise the customer that the vehicle is equipped with an adaptive transmission shift strategy which allows the computer to learn. The relearning process may require a short period of driving until the shifting parameters are set.