GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC C-Series Medium Duty Truck B7 🢒 Engine 🢒 Engine Controls - 7.4L 🢒 Mass Airflow Sensor Replacement

Removal Procedure

    Object Number: 422645 Size: SH

    Important: Take care when handling the MAF.

       • DO NOT dent, puncture, or otherwise damage the honeywell located at the air inlet end of the MAF.
       •  DO NOT touch the sensing elements or allow anything (including solvents and lubricants) to come in contact with them.
       •  A small amount of GM lubricant (P/N 99855406) may be used on the air duct only to aid in installation.
       • Do Not drop or roughly handle the MAF.

  1. Loosen the clamp (3) to the air cleaner outlet front duct to the MAF sensor (4).
  2. Loosen the clamp on the air cleaner assembly (1) to the MAF sensor (4).
  3. Remove the MAF electrical connector.
  4. Carefully remove the MAF sensor (4) from the ducts.

Installation Procedure

    Object Number: 422645 Size: SH

    Important: Embossed arrows on the MAF sensor indicate proper air flow direction and must point toward the engine.

  1. Install the MAF sensor (4) to the air cleaner assembly (1).
  2. Tighten the clamp.
  3. Install the air cleaner outlet front duct to the MAF sensor (4).
  4. Tighten the clamp (3).
  5. Connect the electrical connector.