GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 GMC C Sierra - 2WD 🢒 Engine 🢒 Engine Controls - 6.6L 🢒 Engine Wiring Harness Assembly Replacement

Removal Procedure

    Object Number: 786976 Size: SH
  1. Disconnect negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  2. Remove engine sight shield.
  3. Remove air intake duct. Refer to Air Cleaner Inlet Duct Replacement .
  4. Disconnect fuel injection control module.

    5. Object Number: 786973 Size: SH
  5. Disconnect fuel filter/heater assembly connectors.

    6. Object Number: 786980 Size: SH
  6. Disconnect right rear fuel injector harness connector.

    7. Object Number: 759733 Size: SH
  7. Disconnect right front fuel injector harness connector.

    8. Object Number: 740438 Size: SH
  8. Disconnect turbo boost sensor.

    9. Object Number: 786983 Size: SH
  9. Remove sight shield hold-down bracket.

    10. Object Number: 740506 Size: SH
  10. Disconnect coolant temperature sensor.

    11. Object Number: 668427 Size: SH
  11. Remove turbo water inlet hose.

    12. Object Number: 674653 Size: SH
  12. Disconnect engine harness bulk connectors.

    13. Object Number: 674680 Size: SH
  13. Remove bolts retaining bulk connectors to bracket.

    14. Object Number: 664853 Size: SH
  14. Remove left turbo air outlet hose.

    15. Object Number: 786986 Size: SH
  15. Disconnect left front fuel injector harness connector.

    16. Object Number: 786988 Size: SH
  16. Disconnect left rear fuel injector harness connector.

    17. Object Number: 786977 Size: SH
  17. Disconnect fuel rail temperature sensor connector.

    18. Object Number: 786978 Size: SH
  18. Disconnect glow plug relay connectors.

    19. Object Number: 786991 Size: SH
  19. Disconnect oil level harness connector.

    20. Object Number: 739503 Size: SH
  20. Disconnect BARO sensor connector.

    21. Object Number: 786994 Size: SH
  21. Disconnect fuel rail pressure sensor connector.
  22. Raise vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  23. Remove front lower skid plate.

    24. Object Number: 786970 Size: SH
  24. Disconnect crankshaft position sensor.

    25. Object Number: 742170 Size: SH
  25. Disconnect camshaft position sensor.

    26. Object Number: 786972 Size: SH
  26. Remove bolts retaining engine harness grounds.
  27. Lower vehicle.

    28. Object Number: 786996 Size: SH
  28. Unroute and lift engine wiring harness assembly for access to fuel rail pressure regulator.
  29. Disconnect fuel rail pressure regulator.

    30. Object Number: 660421 Size: SH
  30. Remove engine wiring harness from vehicle.

Installation Procedure

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

    2. Object Number: 786996 Size: SH
  2. Connect fuel rail pressure regulator connector.
  3. Route engine wiring harness to engine.

    4. Object Number: 786972 Size: SH
  4. Raise vehicle.
  5. Install bolts to retain engine wiring harness grounds.

    6. Object Number: 742170 Size: SH
  6. Connect camshaft position sensor.

    7. Object Number: 786970 Size: SH
  7. Connect crankshaft position sensor.
  8. Install front lower skid plate.
  9. Lower vehicle.

    10. Object Number: 786994 Size: SH
  10. Connect fuel rail pressure sensor connector.

    11. Object Number: 739503 Size: SH
  11. Connect BARO sensor connector.

    12. Object Number: 786991 Size: SH
  12. Connect oil level sensor harness connector.

    13. Object Number: 786978 Size: SH
  13. Connect glow plug relay connectors.

    14. Object Number: 786977 Size: SH
  14. Connect fuel rail temperature sensor harness connector.

    15. Object Number: 786988 Size: SH
  15. Connect left rear fuel injector harness connector.

    16. Object Number: 786986 Size: SH
  16. Connect left front fuel injector harness connector.

    17. Object Number: 664853 Size: SH
  17. Install left turbo air outlet hose.

    18. Object Number: 674680 Size: SH
  18. Install bolts to retain bulk connectors to bracket.

    19. Object Number: 674653 Size: SH
  19. Connect engine harness bulk connectors.

    20. Object Number: 668427 Size: SH
  20. Install turbo water inlet hose.

    21. Object Number: 740506 Size: SH
  21. Connect coolant temperature sensor.

    22. Object Number: 786983 Size: SH
  22. Install engine sight shield hold-down bracket.

    23. Object Number: 740438 Size: SH
  23. Connect turbo boost sensor.

    24. Object Number: 759733 Size: SH
  24. Connect right front fuel injector harness connector.

    25. Object Number: 786980 Size: SH
  25. Connect right rear fuel injector harness connector.

    26. Object Number: 786973 Size: SH
  26. Connect fuel filter/heater assembly connectors.

    27. Object Number: 786976 Size: SH
  27. Connect fuel injection control module.
  28. Install air intake duct. Refer to Air Cleaner Inlet Duct Replacement .
  29. Install engine sight shield.
  30. Connect negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.