DDEC 3 to DDEC4 12.7

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Tomek373, Aug 24, 2021.

  1. Tomek373

    Tomek373 Bobtail Member

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    Mar 12, 2021
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    Hello guys i have 97 Classic with 12.7 s60 it originally came with DDEC 3 motor which i swapped for a 2012 Reman DDEC 4. The ecu I still have is DDEC 3( and I think it’s set at 350hp because truck has no balls) and I want to swap it for ddec 4 and get it programmed to 470 since I have mk model. Would I have to do any rewiring or change my harnesses to do the swap or it’s just plug and play with original harness?
    Thank you in advance!
     
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  3. jamespmack

    jamespmack Road Train Member

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    3 to 4 should be nothing but programming.
     
  4. Rideandrepair

    Rideandrepair Road Train Member

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    Plugs are the same. I’ve read that some programming is different for sensor readings. Not sure if that applies to your set up or not. Supposedly the temp sensors can read differently, causing the fan to engage too early, or worse, too late, if the engine has ddec3 sensors and ddec4 program. Engine actually runs hotter than gauge readings.
     
  5. Tomek373

    Tomek373 Bobtail Member

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    Mar 12, 2021
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    I have a DDEC 4 engine a 2012 reman by Detroit on ddec 3 ecu so I think I should be ok
     
    Rideandrepair Thanks this.
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