The cars computer is known as the "PCM"...powertrain control module. When things go wrong, it sets (retains) DTC's or Diagnostic Trouble Codes that refer to the failure. Serious troubles will turn on the SES (service engine soon) light in the dashboard. Ford told me if there is "NO" SES light, there are no DTC's setmeangreen00zx3 said:and what does OBD II DTC stand for???