GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Chevy K Silverado - 4WD 🢒 Engine 🢒 Engine Controls - 6.6L 🢒 Engine Wiring Harness Assembly Replacement

Removal Procedure

    Object Number: 786976 Size: SH
  1. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  2. Remove the air cleaner. Refer to Air Cleaner Assembly Replacement .
  3. Disconnect the fuel injection control module electrical connectors (1).

    4. Object Number: 877275 Size: SH
  4. Loosen the charged air cooler outlet duct clamp (1).

    5. Important: Do not use a screwdriver or other tool to pry the hose loose. The hose can be torn or damaged. Loosen the hose by twisting.

  5. Remove the charged air cooler outlet duct.

    6. Object Number: 786973 Size: SH
  6. Disconnect the following electrical connectors:
    7. • Water-in-fuel sensor (1)
    • Fuel heater (2)

    Object Number: 786980 Size: SH
  7. Disconnect the right rear fuel injector electrical connector (1).

    8. Object Number: 788836 Size: SH
  8. Disconnect the exhaust gas recirculation (EGR) valve solenoid electrical connector (1).

    9. Object Number: 788837 Size: SH
  9. Disconnect the EGR valve vent solenoid electrical connector (1).

    10. Object Number: 788835 Size: SH
  10. Disconnect the EGR valve vacuum sensor electrical connector (1).

    11. Object Number: 788838 Size: SH
  11. Disconnect the EGR throttle valve solenoid electrical connector.

    12. Object Number: 788839 Size: SH
  12. Remove the right side glow plug electrical nuts.
  13. Remove the right side engine harness from the glow plug (1).

    14. Object Number: 788844 Size: SH
  14. Disconnect the right front fuel injector electrical connector (1).

    15. Object Number: 788842 Size: SH
  15. Disconnect the turbocharger boost sensor electrical connector (1).

    16. Object Number: 786983 Size: SH
  16. Remove the sight shield hold-down bolt and bracket (1).

    17. Object Number: 740506 Size: SH
  17. Disconnect the engine coolant temperature (ECT) sensor electrical connector (1).

    18. Object Number: 668427 Size: SH
  18. Reposition the turbocharger water inlet hose clamp.
  19. Remove the turbocharger water inlet hose.

    20. Object Number: 687052 Size: SH
  20. Remove the turbocharger coolant bypass valve.
  21. Remove the glow plug relay. Refer to Glow Plug Relay Replacement .

    22. Object Number: 674653 Size: SH
  22. Disconnect the engine harness electrical connectors.

    23. Object Number: 674680 Size: SH
  23. Remove the bulk connector bolts from the bracket (1).

    24. Object Number: 877281 Size: SH
  24. Loosen the charged air cooler inlet duct to turbocharger clamp (1).

    25. Important: Do not use a screwdriver or other tool to pry the hose loose. The hose can be torn or damaged. Loosen the hose by twisting.

  25. Remove the charged air cooler inlet duct from the turbocharger.

    26. Object Number: 687021 Size: SH
  26. Reposition the positive crankcase ventilation (PCV) hose clamp.
  27. Remove the PCV hose from the left valve cover.

    28. Object Number: 786986 Size: SH
  28. Disconnect the left front fuel injector electrical connector (1).

    29. Object Number: 786988 Size: SH
  29. Disconnect the left rear fuel injector electrical connector (1).

    30. Object Number: 786977 Size: SH
  30. Disconnect the fuel rail temperature sensor electrical connector (1).

    31. Object Number: 788841 Size: SH
  31. Disconnect the glow plug controller electrical connectors (1).

    32. Object Number: 788847 Size: SH
  32. Remove the fuel pipe retainer nut at the valve cover.
  33. Remove the fuel pipe retainer (2).

    34. Object Number: 788840 Size: SH
  34. Remove the left front wheelhouse panel. Refer to Wheelhouse Panel Replacement in Body Front End.
  35. Remove the left side glow plug electrical nuts.
  36. Remove the left side engine harness from the glow plugs (1).

    37. Object Number: 788846 Size: SH
  37. Disconnect the oil level electrical connector (1).

    38. Object Number: 739503 Size: SH
  38. Disconnect the barometric pressure (BARO) sensor electrical connector (1).

    39. Object Number: 786994 Size: SH
  39. Disconnect the fuel rail pressure sensor electrical connector (1).
  40. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.

    41. Object Number: 349061 Size: SH
  41. Remove the engine shield bolts and shield.

    42. Object Number: 786970 Size: SH
  42. Disconnect the crankshaft position (CKP) sensor electrical connector.

    43. Object Number: 742170 Size: SH
  43. Disconnect the camshaft position (CMP) sensor electrical connector (1).

    44. Object Number: 786972 Size: SH
  44. Remove the engine harness ground bolts (1).
  45. Lower the vehicle.

    46. Object Number: 786996 Size: SH
  46. Unroute and lift up the engine wiring harness for access to fuel pressure regulator.
  47. Disconnect the fuel pressure regulator electrical connector (1).

    48. Object Number: 660421 Size: SH
  48. Remove the engine wiring harness.

Installation Procedure

    Object Number: 660421 Size: SH
  1. Install the engine wiring harness.

    2. Object Number: 786996 Size: SH
  2. Connect the fuel pressure regulator electrical connector (1).
  3. Route the engine wiring harness to the engine.

    4. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 786972 Size: SH
  4. Raise the vehicle.
  5. Install the engine wiring harness ground bolts (1).

    6. Tighten
    Tighten the bolts to 34 N·m (25 lb ft).


    Object Number: 742170 Size: SH
  6. Connect the CMP sensor electrical connector (1).

    7. Object Number: 786970 Size: SH
  7. Connect the CKP sensor electrical connector.

    8. Object Number: 349061 Size: SH
  8. Install the engine shield and bolts.

    9. Tighten
    Tighten the bolts to 20 N·m (15 lb ft).

  9. Lower the vehicle.

    10. Object Number: 786994 Size: SH
  10. Connect the fuel rail pressure sensor electrical connector (1).

    11. Object Number: 739503 Size: SH
  11. Connect the BARO sensor electrical connector (1).

    12. Object Number: 788846 Size: SH
  12. Connect the oil level sensor electrical connector (1).

    13. Object Number: 788840 Size: SH
  13. Install the left side engine harness to the glow plugs (1).
  14. Install the glow plug electrical nuts.

    15. Tighten
    Tighten the nuts to 2 N·m (18 lb in).

  15. Install the left inner wheelhouse panel. Refer to Wheelhouse Panel Replacement in Body Front End.

    16. Object Number: 788847 Size: SH
  16. Install the fuel pipe retainer (2).
  17. Install the fuel pipe retainer nut at the valve cover.

    18. Tighten
    Tighten the nut to 8 N·m (70 lb in).


    Object Number: 788841 Size: SH
  18. Connect the glow plug controller electrical connectors (1).

    19. Object Number: 786977 Size: SH
  19. Connect the fuel rail temperature sensor electrical connector (1).

    20. Object Number: 786988 Size: SH
  20. Connect the left rear fuel injector electrical connector (1).

    21. Object Number: 786986 Size: SH
  21. Connect the left front fuel injector electrical connector (1).

    22. Object Number: 687021 Size: SH
  22. Install the PCV hose to valve cover.
  23. Position the PCV hose clamp.

    24. Object Number: 877281 Size: SH
  24. Install the charged air cooler inlet duct to the turbocharger.
  25. Align the mark on the duct (2) with the mark on the turbocharger.
  26. Position the clamp (1) as shown for proper clearance.

    27. Tighten
    Tighten the clamp to 6 N·m (53 lb in).


    Object Number: 674680 Size: SH
  27. Install the bulk connector bolts (1) to the bracket.

    28. Tighten
    Tighten the bolts to 21 N·m (15 lb ft).


    Object Number: 674653 Size: SH
  28. Connect the engine harness electrical connectors.
  29. Install the glow plug relay. Refer to Glow Plug Relay Replacement .

    30. Object Number: 687052 Size: SH
  30. Install the turbocharger coolant bypass valve.

    31. Tighten
    Tighten the valve to 60 N·m (44 lb ft).


    Object Number: 668427 Size: SH
  31. Install the turbocharger water inlet hose.
  32. Position the turbocharger water inlet hose clamp.

    33. Object Number: 740506 Size: SH
  33. Connect the ECT sensor electrical connector (1).

    34. Object Number: 786983 Size: SH
  34. Install the engine sight shield hold-down bracket (1) and bolt.

    35. Tighten
    Tighten the bolt to 10 N·m (89 lb in).


    Object Number: 788842 Size: SH
  35. Connect the turbocharger boost sensor electrical connector (1).

    36. Object Number: 788844 Size: SH
  36. Connect the right front fuel injector electrical connector (1).

    37. Object Number: 788839 Size: SH
  37. Install the right side engine harness to the glow plugs (1).
  38. Install the right side glow plug electrical nuts.

    39. Tighten
    Tighten the nuts to 2 N·m (18 lb in).


    Object Number: 788838 Size: SH
  39. Connect the EGR throttle valve solenoid electrical connector (1).

    40. Object Number: 788835 Size: SH
  40. Connect the EGR vacuum sensor electrical connector (1).

    41. Object Number: 788837 Size: SH
  41. Connect the EGR vent solenoid electrical connector (1).

    42. Object Number: 788836 Size: SH
  42. Connect the EGR valve solenoid electrical connector (1).

    43. Object Number: 786980 Size: SH
  43. Connect the right rear fuel injector electrical connector (1).

    44. Object Number: 786973 Size: SH
  44. Connect the following electrical connectors:
    45. • Water-in-fuel sensor (1)
    • Fuel heater (2)

    Object Number: 877275 Size: SH
  45. Install the charged air cooler outlet duct to the intake.
  46. Tighten the charged air cooler outlet duct clamp (1).

    47. Tighten
    Tighten the clamp to 6 N·m (53 lb in).


    Object Number: 786976 Size: SH
  47. Connect the fuel injection control module electrical connectors (1).
  48. Install the air cleaner. Refer to Air Cleaner Assembly Replacement .
  49. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.