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Perform the following procedures for removal and installation of the DDEC-ECUcontrol unit. ‪

DDEC Electronic Control Unit Removal

Remove the DDEC-ECU Control Unit as follows: ‪

  1. Disconnect the batteries.
  2. Open the hood.
  3. Remove the heat exchanger mounting bolts, but do not disconnect the fuel lines to the heat exchanger. See Figure 42112 .

    1. DDEC-ECU Control Unit ‪

    8. Fuel Heat Exchanger Mounting Bolt ‪

    2. Engine Electrical Connector ‪

    9. Fuel Heat Exchanger Inlet ‪

    3. Vehicle Electrical Connector ‪

    10. Banjo (Hollow-Core) Bolt ‪

    4. Spacer ‪

    11. Banjo Fitting ‪

    5. DDEC-ECU Mounting Bolt ‪

    12. Fuel Heat Exchanger ‪

    6. Engine Wiring Harness ‪

    13. Heat Exchanger Case Bolt ‪

    7. Fuel Feed Line ‪

    14. DDEC-ECU Case Bolt ‪

    DDEC-ECU Control Unit

  4. Lift up the slide on the locking unit to release the vehicle wiring harness connector and disconnect it from the DDEC-ECU unit. See Figure 42113 .

    1. Vehicle Electrical Connector ‪

    2. Vehicle Wiring Harness ‪

    Vehicle Electrical Connector

  5. Rotate the safety latch down to release the engine wiring harness connector and disconnect it from the DDEC-ECU unit. See Figure 42114 .

    1. Engine Wiring Harness ‪

    3. Engine Electrical Connector ‪

    2. Safety latch ‪

    Engine Electrical Connector

  6. Remove the mounting bolts and rubber spacers holding the DDEC-ECU control unit to the engine. Then remove the unit.

    Note: Do not disassemble the DDEC-ECU control unit. It cannot be serviced.

DDEC Electronic Control Unit Installation

Install the DDEC-ECU Control Unit as follows: ‪

  1. Position the spacers, DDEC-ECU control unit, and mounting bolts on the cylinder block, as removed.
  2. Install the DDEC-ECU control unit on the cylinder block. Tighten the mounting bolts 15 Nm (11 lbft).
  3. Install the fuel heat exchanger on the DDEC-ECU and tighten the mounting bolts 8 Nm (6 lbft).
  4. Connect the vehicle wiring harness to the DDEC-ECU. Pull down on the locking unit to lock it in place.
  5. Connect the engine wiring harness to the DDEC-ECU. Rotate the safety latch upward to lock it in place.
  6. If a new DDEC-ECU control unit was installed, transfer the customer parameter list to it, using minidiag2.
  7. Connect the batteries.


    Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer, birth defects, and other reproductive harm.

    • Always start and operate an engine in a well ventilated area.
    • If operating an engine in an enclosed area, vent the exhaust to the outside.
    • Do not modify or tamper with the exhaust system or emission control system.
  8. Close the hood. Then check for normal operation.