GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2004 🢒 CTS 🢒 Engine 🢒 Engine Mechanical - 2.6L and 3.2L 🢒 Intake Plenum Replacement

Removal Procedure

    Object Number: 785802 Size: SH
  1. Remove the intake plenum air inlet hose clamps and hoses from the throttle body.
  2. Disconnect the fuel pressure regulator atmospheric vent tube from the bottom of the throttle body.

    3. Object Number: 345338 Size: SH
  3. Remove the bolts securing the throttle body to the intake plenum.
  4. Remove the throttle body from the intake plenum and crankcase vent adapter, allowing it to be supported by the throttle body inlet heater hose.
  5. Remove the throttle body O-ring seals.

    6. Object Number: 821099 Size: SH
  6. Remove the 3 bolts securing the crankcase vent adapter to the intake plenum.
  7. Lift the crankcase vent adapter from the intake plenum, and position aside.

    8. Object Number: 794128 Size: SH
  8. Disconnect the vacuum brake booster hose retainer (1) from the rear of the intake plenum-RHD only.
  9. Disconnect the crankcase ventilation dirty air hose retainer (2) from the fuel pipe.

    10. Object Number: 785730 Size: SH
  10. Remove the remote power steering fluid reservoir mounting bolts (1, 3) ONLY, and position aside.

    11. Object Number: 349112 Size: SH
  11. Disconnect the electrical connector (1) and vacuum hose (2) from the switchover valve at the rear of the plenum.

    12. Object Number: 785825 Size: SH
  12. Remove the bolt (1) securing the throttle body heater inlet hose/pipe to the intake plenum (2).
  13. Disconnect the vacuum brake booster hose (3) from the vacuum source.

    14. Object Number: 797516 Size: SH
  14. Remove the 2 bolts securing the engine control module (ECM) bracket to the intake plenum.

    15. Object Number: 764826 Size: SH
  15. Remove the intake plenum bolt caps.
  16. Remove the intake plenum bolts.
  17. Lift the intake plenum from the intake manifold.
  18. Remove the intake plenum O-ring seals.
  19. Mask off the open ports to the intake manifold, in order to prevent foreign objects from entering the engine.
  20. Disassemble the intake plenum if necessary. Refer to Intake Plenum Manifold Disassemble .
  21. Clean and inspect the intake plenum. Refer to Intake Plenum Manifold Cleaning and Inspection .

Installation Procedure
  1. Assemble the intake plenum if necessary. Refer to Intake Plenum Manifold Assemble .
  2. Remove the masking from the intake plenum ports and ensure the sealing surfaces are clean and dry.
  3. Lightly coat the intake plenum O-ring seals with clean engine oil and install to the intake manifold.

    4. Object Number: 764826 Size: SH
  4. Position the intake plenum to the intake manifold, aligning the pins.

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

  5. Install the intake plenum bolts.

    6. Tighten
    Tighten the intake plenum bolts to 20 N·m (15 lb ft).

  6. Install the intake plenum bolt caps.

    7. Object Number: 785761 Size: SH
  7. Install the 2 bolts securing the ECM bracket to the intake plenum.

    8. Tighten
    Tighten the ECM bracket bolts to 8 N·m (71 lb in) in sequence 2-3.


    Object Number: 785825 Size: SH
  8. Connect the vacuum brake booster hose (3) to the vacuum source.
  9. Install the bolt (1) securing the throttle body heater inlet hose/pipe to the intake plenum (2).

    10. Tighten
    Tighten the throttle body heater inlet hose/pipe bolt to 9 N·m(80 lb in).


    Object Number: 349112 Size: SH
  10. Connect the electrical connector (1) and vacuum hose (2) to the switchover valve at the rear of the plenum.

    11. Object Number: 785730 Size: SH
  11. Position the remote power steering fluid reservoir (2) to the engine.
  12. Install the remote power steering fluid reservoir mounting bolts (1, 3).

    13. Tighten

    • Tighten the remote power steering fluid reservoir mounting bolts (1) to intake plenum to 9 N·m (80 lb in).
    • Tighten the remote power steering fluid reservoir mounting bolt (3) to cylinder head to 25 N·m (18 lb ft).

    Object Number: 794128 Size: SH
  13. Connect the vacuum brake booster hose retainer (1) to the rear of the intake plenum-RHD only.
  14. Connect the crankcase ventilation dirty air hose retainer (2) to the fuel pipe.

    15. Object Number: 821099 Size: SH
  15. Apply clean engine oil to the crankcase vent adapter seal.
  16. Position the crankcase vent adapter to the intake plenum.
  17. Install the 3 bolts securing the crankcase vent adapter to the intake plenum.

    18. Tighten
    Tighten the crankcase vent tube adapter bolts to 8 N·m (71 lb in).

  18. Inspect the following O-ring seals and replace if necessary:
    19. • The throttle body
    • The crankcase vent tubes
  19. Lightly lubricate the O-ring seals with clean engine oil.

    20. Object Number: 345338 Size: SH
  20. Position the throttle body to the intake plenum and crankcase vent adapter.
  21. Install the bolts securing the throttle body to the intake plenum.

    22. Tighten
    Tighten the throttle body bolts to 8 N·m (71 lb in).

  22. Connect the fuel pressure regulator atmospheric vent tube to the bottom of the throttle body.

    23. Object Number: 785802 Size: SH
  23. Install the intake plenum air inlet hose clamps and hoses to the throttle body.