GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2005 🢒 GMC C Sierra - 2WD 🢒 Engine 🢒 Engine Controls - 6.6L (LLY) 🢒 Engine Wiring Harness Assembly Replacement

Removal Procedure

    Object Number: 1334381 Size: SH
  1. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  2. Remove the intake manifold cover. Refer to Intake Manifold Cover Replacement in Engine Mechanical - 6.6L (LLY).
  3. Remove both front wheelhouse panels. Refer to Wheelhouse Panel Replacement in Body Front End.
  4. Remove the air cleaner outlet duct. Refer to Air Cleaner Outlet Duct Replacement .
  5. Loosen the charged air cooler outlet duct to intake hose clamp.

    6. 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.

  6. Remove the charged air cooler outlet duct from the intake.

    7. Object Number: 1334380 Size: SH
  7. Loosen the charged air cooler inlet duct connector to turbocharger clamp (1).

    8. 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.

  8. Remove the charged air cooler inlet duct connector (4) from the turbocharger.

    9. Object Number: 1334881 Size: SH
  9. Disconnect the fuel injection control module electrical connectors.
  10. Cut the tie strap attaching the harness to the bracket.

    11. Object Number: 1335443 Size: SH
  11. Remove the left glow plug harness bracket bolts.

    12. Object Number: 1335450 Size: SH
  12. Remove the right glow plug harness bracket bolts.
  13. Remove the positive crankcase ventilation (PCV) hose/pipe. Refer to Positive Crankcase Ventilation Hose/Pipe/Tube Replacement in Engine Mechanical - 6.6L (LLY).

    14. Object Number: 1335413 Size: SH
  14. Disconnect the engine coolant temperature (ECT) sensor electrical connector.

    15. Object Number: 1335463 Size: SH
  15. Disconnect the exhaust gas recirculation (EGR) valve electrical connector.

    16. Object Number: 1334862 Size: SH
  16. Disconnect the camshaft position (CMP) sensor electrical connector.

    17. Object Number: 1335467 Size: SH
  17. Remove the 2 ground bolts.

    18. Object Number: 1335470 Size: SH
  18. Disconnect the crankshaft position (CKP) sensor electrical connector.

    19. Object Number: 1335476 Size: SH
  19. Remove the tie strap from the electrical harness.

    20. Object Number: 1409327 Size: SH
  20. Disconnect the main engine electrical harness connectors. Lift up on the latches (1) in order to disconnect the connectors.
  21. Open the harness clip (2).
  22. Remove the main engine electrical harness connectors.

    23. Object Number: 1334921 Size: SH
  23. Disconnect the barometric sensor electrical connector.

    24. Object Number: 1334916 Size: SH
  24. Remove the main engine electrical harness connector bolts.

    25. Object Number: 1335482 Size: SH
  25. Disconnect the fuel pressure control valve electrical connector.

    26. Object Number: 1335490 Size: SH
  26. Disconnect the turbocharger boost sensor electrical connector.

    27. Object Number: 1335526 Size: SH
  27. Disconnect the oil level sensor electrical harness connector.

    28. Object Number: 1335528 Size: SH
  28. Disconnect the fuel temperature sensor electrical connector.

    29. Object Number: 1335531 Size: SH
  29. Disconnect the glow plug controller electrical connector.

    30. Object Number: 1409333 Size: SH
  30. Disconnect the glow plug controller battery feed electrical connector (1).

    31. Object Number: 1334926 Size: SH

    Important: Note the wire routing prior to removal.

  31. Disconnect and remove the turbocharger vane position sensor.

    32. Object Number: 1335536 Size: SH

    Notice: Label all the injector electrical connectors before the connectors are removed in order to prevent reconnecting to the wrong injector. Failure to properly connect the injectors in the correct sequence will cause severe engine damage.

  32. Disconnect the fuel injector electrical connectors.

    33. Object Number: 1335540 Size: SH
  33. Disconnect the turbocharger vane control solenoid valve.

    34. Object Number: 1335543 Size: SH
  34. Disconnect the fuel rail pressure sensor electrical connector.

    35. Object Number: 1335546 Size: SH
  35. Disconnect the oil pressure sensor electrical connector.

    36. Object Number: 1335549 Size: SH
  36. Remove the oil level sensor harness bolt.

    37. Object Number: 1336490 Size: SH
  37. Remove the glow plug controller bolts.
  38. Remove the glow plug controller.
  39. Remove the glow plug electrical connector nuts.

    40. Object Number: 1335560 Size: SH
  40. Remove the engine wiring harness.

Installation Procedure

    Object Number: 1335560 Size: SH
  1. Install the engine wiring harness.

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


    Object Number: 1336490 Size: SH
  2. Install the glow plug electrical connector nuts.

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

  3. Install the glow plug controller.
  4. Install the glow plug controller bolts.

    5. Tighten
    Tighten the bolts to 10 N·m (89 lb in).


    Object Number: 1335549 Size: SH
  5. Install the oil level sensor harness bolt.

    6. Tighten
    Tighten the bolt to 40 N·m (30 lb ft).


    Object Number: 1335546 Size: SH
  6. Connect the oil pressure sensor electrical connector.

    7. Object Number: 1335543 Size: SH
  7. Connect the fuel rail pressure sensor electrical connector.

    8. Object Number: 1335540 Size: SH
  8. Connect the turbocharger vane control solenoid valve.

    9. Object Number: 1335536 Size: SH
  9. Connect the fuel injector electrical connectors.

    10. Object Number: 1334926 Size: SH
  10. Install and connect the turbocharger vane position sensor.

    11. Object Number: 1409333 Size: SH
  11. Connect the glow plug controller battery feed electrical connector (1).

    12. Object Number: 1335531 Size: SH
  12. Connect the glow plug controller electrical connector.

    13. Object Number: 1335528 Size: SH
  13. Connect the fuel temperature sensor electrical connector.

    14. Object Number: 1335526 Size: SH
  14. Connect the oil level sensor electrical harness connector.

    15. Object Number: 1335490 Size: SH
  15. Connect the turbocharger boost sensor electrical connector.

    16. Object Number: 1335482 Size: SH
  16. Connect the fuel pressure control valve electrical connector.

    17. Object Number: 1334916 Size: SH
  17. Install the main engine electrical harness connector screws.

    18. Tighten
    Tighten the screws to 10 N·m (89 lb in).


    Object Number: 1334921 Size: SH
  18. Connect the barometric sensor electrical connector.

    19. Object Number: 1409327 Size: SH
  19. Connect the main engine electrical harness connectors.
  20. Push down on the latches (1) in order to connect the connectors.
  21. Close the harness clip (2).

    22. Object Number: 1335476 Size: SH
  22. Install a NEW tie strap to the electrical harness.

    23. Object Number: 1335470 Size: SH
  23. Connect the CKP sensor electrical connector.

    24. Object Number: 1335467 Size: SH
  24. Install the 2 ground bolts.

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


    Object Number: 1334862 Size: SH
  25. Connect the CMP sensor electrical connector.

    26. Object Number: 1335463 Size: SH
  26. Connect the EGR valve electrical connector.

    27. Object Number: 1335413 Size: SH
  27. Connect the ECT sensor electrical connector.
  28. Install the PCV hose/pipe. Refer to Positive Crankcase Ventilation Hose/Pipe/Tube Replacement in Engine Mechanical - 6.6L (LLY).

    29. Object Number: 1335450 Size: SH
  29. Install the right glow plug harness bracket bolts.

    30. Tighten
    Tighten the bolts to 10 N·m (89 lb in).

  30. Install the right glow plug connectors to the glow plugs.

    31. Tighten
    Tighten the glow plug connector nuts to 2 N·m (18 lb in).


    Object Number: 1335443 Size: SH
  31. Install the left glow plug harness bracket bolts.

    32. Tighten
    Tighten the bolts to 10 N·m (89 lb in.

  32. Install the left glow plug connectors to the glow plugs.

    33. Tighten
    Tighten the glow plug connector nuts to 2 N·m (18 lb in).


    Object Number: 1334881 Size: SH
  33. Connect the fuel injection control module electrical connectors.
  34. Install a NEW tie strap attaching the harness to the bracket.

    35. Object Number: 1334380 Size: SH
  35. Remove the tape from the turbocharger openings.

    36. Important: Lubricate the end of the duct prior to installation.

  36. Install the charged air cooler inlet duct connector (4) to the turbocharger.
  37. Tighten the charged air cooler inlet duct connector to turbocharger clamp (1).

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


    Object Number: 1334381 Size: SH

    Important: Lubricate the end of the duct prior to installation.

  38. Install the charged air cooler outlet duct to the intake.
  39. Tighten the charged air cooler outlet duct to intake hose clamp.

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

  40. Install the air cleaner outlet duct. Refer to Air Cleaner Outlet Duct Replacement .
  41. Install both front wheelhouse panels. Refer to Wheelhouse Panel Replacement in Body Front End.
  42. Install the intake manifold cover. Refer to Intake Manifold Cover Replacement in Engine Mechanical - 6.6L (LLY).
  43. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.