GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 Sonoma Pickup - 2WD 🢒 Body and Accessories 🢒 Wiring Systems 🢒 Secondary Air Injection Check Valve and Check Valve Pipe Replacement - Bank 1

Removal Procedure
  1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  2. For a 2WD vehicle, skip steps 5 and 6.

    3. For a 4WD vehicle, skip steps 3 and 4.


    Object Number: 372939 Size: SH
  3. Remove the AIR shield mounting bolts.

    4. Object Number: 372933 Size: SH
  4. Remove the AIR shield.

    5. Object Number: 325346 Size: SH
  5. Remove the retaining bolts from the steering linkage shield.

    6. Object Number: 325348 Size: SH
  6. Remove the steering linkage shield.

    7. Object Number: 372967 Size: SH
  7. Remove the AIR reactor pipe assembly bolts.

    8. Object Number: 372989 Size: SH
  8. Remove the AIR reactor pipe assembly and gasket.

    9. Object Number: 416594 Size: SH
  9. Disconnect the reactor pipe assembly from the reactor pipes by releasing the spring clamps.

    10. Object Number: 373093 Size: SH

    Important: Perform this last step only if the check valve needs replacement.

  10. Separate the check valve from the reactor pipe by loosening the spring clamp and pipe locknut.

Installation Procedure

    Object Number: 373093 Size: SH

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

    Important: Skip the first step if the check valve has not been removed.

  1. Connect the reactor pipe and check valve by installing the spring clamp and tightening the pipe locknut.

    2. Tighten
    Tighten the locknut to 10 N·m (89 lb in).


    Object Number: 372989 Size: SH

    Important: Clean the manifold mounting surface of any debris or carbon buildup. An airhole could adversely effect vehicle emissions and driveability.

  2. Install the reactor pipe and gasket.

    3. Object Number: 372967 Size: SH
  3. Install the reactor pipe assembly bolts.

    4. Tighten

        • Tighten the mounting bolts to 25 N·m (18 lb ft).
        • Tighten the reactor pipe assembly retainer bolt to 40 N·m (30 lb ft).

    Object Number: 416594 Size: SH
  4. Connect the reactor pipe assembly to the reactor pipes by installing the spring clamps.
  5. For a 2WD vehicle, skip steps 8 and 9.

    6. For a 4WD vehicle, skip steps 6 and 7.


    Object Number: 372933 Size: SH
  6. Align the AIR shield.

    7. Object Number: 372939 Size: SH
  7. Install the AIR shield mounting bolts.

    8. Tighten
    Tighten the bolts to 33 N·m (24 lb ft).


    Object Number: 325348 Size: SH
  8. Align the steering linkage shield.

    9. Object Number: 325346 Size: SH
  9. Install the linkage shield mounting bolts.

    10. Tighten
    Tighten the bolts to 33 N·m (24 lb ft).

  10. Lower the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.