DDEC III & IV rebuilds, circuit board repairs, and component replacements

I define a rebuild as the replacement of any or all component(s) that is close to reaching or has already reached the end of it’s recommended service life as defined by the manufacturer of that component. So that’s new memory, a new battery and a few other parts. I’ve seen in some Detroit reman ecms that make me feel pretty good about that standard. Below is a 2012 reman DDEC IV and a 1998 DDEC IV. Motorola made the DDEC IV from 1998 to 1999 before another manufacturer took over. If you visually compare the components you’ll see the original Motorola parts (including memory) are all there. In 2012 the memory would have already been beyond it’s service life but the only thing that was changed was the battery. So if the ECM is clean, original, undamaged, fully functional, with no reported problems by the owner other than active memory and battery faults then a standard rebuild that includes the memory and battery replacement will be what happens. If oil, fuel, or water has contaminated or oxidized the circuit board traces or circuit board components then an additional fee gets added to the job to cover the extra work. The additional costs range from $50 to $250 depending on the amount of extra work that was needed to get the circuit board and its components cleaned up. If circuit board traces are shorted, broken or other damage is found and/or other major components are damaged and need replaced then the job gets upgraded to a repair.

In 2019 I rebuilt a DDEC IV with over 2 million miles logged.

Estimated Cost


$500* + return shipping

  • *If circuit board is contaminated with oil, fuel, or has oxidation from water intrusion +$50 to +$250
  • *If damaged then job upgrades from a rebuild to a repair.
  • Average job completion time is 2 business days provided other scheduled jobs are not pending.

DDEC III & IV circuit board repairs and component replacement

When the circuit board or circuit board component in a DDEC suffers damage that results in the loss of some or all ecm functions then replacing the damaged ECM and programming the replacement is sometimes the only option.  Other times depending on the severity and location of the damage an ECM circuit board repair could be attempted to reconstruct the damaged section of circuit board and replace any damage components to restore road worthiness and full ECM functionality. Many of the major components inside a DDEC III or DDEC IV had an expected service life of 50 years or more. Premature failures are not uncommon but most of the time when something like the primary microprocessor or the analog to digital converter fails it’s because the component suffered damage from heat, too much current, oxidation damage from water or battery acid, or exposure to voltage that exceeded the components maximum rated voltage. Sometimes the damage is immediately obvious and sometimes it isn’t and requires component specific tests to be identify and locate. The demand for DDEC III and DDEC IV repairs at DCS is growing and thanks in part to advanced inspection, diagnostic and microsoldering tools make microscope aided repairs to trace packed sections of circuit board and fine pitch components feasible and all other repairs more precise and reliable. The net result is more DDEC repairs are go back on the road and less to the core pile and our core pile is shrinking. Some DDECs that were in our core pile are back on the road after completing a successful repair on a DDEC that I at one time believed wasn’t worth a repair attempt.

Estimated Cost


$500-$1050+return shipping

  • When repairs the circuit board or replacement of any integrated circuits or components other than the memory or the internal ECM battery are needed then a rebuild job upgrades to a repair job.
  • Average job completion time is about one to two weeks provided other scheduled jobs are not pending.