Control Module Variant Encoding and Programming
Engine control modules are either variant encoded (M1.x) or Programmed (>M3.x). The possibility exists that an incorrectly coded or programmed control module will cause system faults and or driveability complaints with no faults found.
Prior to condemning a control module as being defective, it should always be considered as a possibility that the control module has been incorrectly coded or programmed. This can simply be checked by connecting the DIS and displaying the control module ID page.