4WD Lamp Illuminated and Diagnostic Trouble Code C140F Active in Final Drive Control
Modules (FDCM) Memory
This bulletin involves verifying FDCM software level and then flash reprogramming of the
FDCM with new software.
Customers may indicate that the ?Service 4WD? indicator in the instrument cluster is
illuminated. They may also indicate that the transfer case will not shift from 4WD High,
4WD Low, and/or Neutral once the lamp is illuminated.
Further investigation identifies that a Diagnostic Trouble Code C140F is stored or active in
the Final Drive Control Modules (FDCM) Memory
