GM Service Manual Online
For 1990-2009 cars only

Fuel Hose/Pipe Replacement - Tee to High Pressure Lock-Off Passenger/Cargo

Tools Required

J 45878 Combustible Gas Detector

Removal Procedure

    Caution: Natural gas is highly flammable. In order to reduce the risk of fire and personal injury, keep sparks, flames, and smoking materials away from the vehicle while you perform the Compressed Natural Gas (CNG) fuel system service.

    Caution: The Compressed Natural Gas (CNG) system operates at pressures up to 24820 kpa (3600 psi). Relieve the CNG fuel system pressure before servicing CNG fuel system components in order to reduce the risk of fire and personal injury.

  1. Relieve the CNG fuel system pressure. Refer to Fuel Pressure Relief .
  2. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical in the G/H Van service manual.
  3. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information in the G/H Van service manual.

  4. Object Number: 893532  Size: SH
  5. Disconnect the fuel line fitting (2) at the check valve tee (1).

  6. Object Number: 893530  Size: SH
  7. Mark the location and remove the fuel line P-clamp mounting bolts (2, 3, 4) and clamps.

  8. Object Number: 893549  Size: SH
  9. Disconnect the fuel line fitting (4) at the high pressure lock-off (HPL) solenoid.
  10. Remove the fuel line from the vehicle.

Installation Procedure

    Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 893530  Size: SH
  1. Install the fuel line and P-clamps (2, 3, 4) into the vehicle.
  2. Tighten
    Tighten the mounting bolts to 10 N·m (89 lb in).


    Object Number: 893532  Size: SH
  3. Connect the CNG fuel line fitting (2) to the check valve tee (1).
  4. Tighten
    Tighten the fuel line fitting to 45 N·m (33 lb ft).


    Object Number: 893549  Size: SH
  5. Connect the CNG fuel line fitting (4) to the HPL.
  6. Tighten
    Tighten the fuel line fitting to 45 N·m (33 lb ft).

  7. Install the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical in the G/H Van service manual.
  8. Start the vehicle and inspect for CNG fuel leaks at the serviced fittings with the J 45878 or an equivalent leak detector.

Fuel Hose/Pipe Replacement - Tee to High Pressure Lock-Off Cutaway

Tools Required

J 45878 Combustible Gas Detector

Removal Procedure

    Caution: Natural gas is highly flammable. In order to reduce the risk of fire and personal injury, keep sparks, flames, and smoking materials away from the vehicle while you perform the Compressed Natural Gas (CNG) fuel system service.

    Caution: The Compressed Natural Gas (CNG) system operates at pressures up to 24820 kpa (3600 psi). Relieve the CNG fuel system pressure before servicing CNG fuel system components in order to reduce the risk of fire and personal injury.

  1. Relieve the CNG fuel system pressure. Refer to Fuel Pressure Relief .
  2. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical in the G/H Van service manual.
  3. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information in the G/H Van service manual.

  4. Object Number: 893532  Size: SH
  5. Disconnect the fuel line fitting (2) at the check valve tee (1).

  6. Object Number: 893549  Size: SH
  7. Disconnect the fuel line fitting (4) at the high pressure lock-off (HPL) solenoid.
  8. Remove the fuel line from the vehicle.

Installation Procedure

    Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 893532  Size: SH
  1. Connect the CNG fuel line fitting (2) to the check valve tee (1).
  2. Tighten
    Tighten the fuel line fitting to 45 N·m (33 lb ft).


    Object Number: 893549  Size: SH
  3. Connect the CNG fuel line fitting (4) to the HPL.
  4. Tighten
    Tighten the fuel line fitting to 45 N·m (33 lb ft).

  5. Install the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical in the G/H Van service manual.
  6. Start the vehicle and inspect for CNG fuel leaks at the serviced fittings with the J 45878 or an equivalent leak detector.