GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

  1. Turn OFF the ignition.
  2. Relieve the fuel pressure. Refer to Fuel Pressure Relief .

  3. Object Number: 788907  Size: SH
  4. Raise the vehicle.
  5. Remove the fuel composition sensor fuel composition sensor (FCS) attachment nuts (1).

  6. Object Number: 788908  Size: SH
  7. Disconnect the FCS inlet and outlet pipes from the FCS. Refer to Plastic Collar Quick Connect Fitting Service .

  8. Object Number: 788909  Size: SH
  9. Disconnect the FCS electrical connector (1).
  10. Remove the FCS and bracket assembly from the frame rail.

  11. Object Number: 788910  Size: SH
  12. Remove the FCS bolts and remove from the bracket.

Installation Procedure


    Object Number: 788910  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.

  1. Install the FCS to the bracket and install bolts.
  2. Tighten
    Tighten bolts to 10 N·m (89 lb in).

  3. Install FCS and bracket assembly to frame.

  4. Object Number: 788907  Size: SH
  5. Install FCS bracket to frame nuts.
  6. Tighten
    Tighten nuts (1) to 17 N·m (13 lb ft).


    Object Number: 788908  Size: SH
  7. Connect the FCS inlet and outlet pipes to the FCS.

  8. Object Number: 788909  Size: SH
  9. Connect the FCS electrical connector (1).
  10. Lower the vehicle.
  11. Start the engine and check for fuel leaks.