1. Relieve the CNG fuel system pressure. Refer to Fuel Pressure Relief .

Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

2. Disconnect the negative battery cable.
3. Remove the AF module assembly. Refer to Alternative Fuel Module Assembly Replacement .
4. Remove the fuel rail. Refer to Fuel Injection Fuel Rail Assembly Replacement in the Engine Controls section of the J Platform gasoline Service Manual.

Tools Required

J 41416 Ultrasonic Leak Detector

1. Install the fuel rail. Refer to Fuel Injection Fuel Rail Assembly Replacement in the Engine Controls section of the J Platform gasoline Service Manual.
2. Install the AF module assembly. Refer to Alternative Fuel Module Assembly Replacement .

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.

3. Connect the negative battery cable.

Tighten
Tighten the bolt to 15 N·m (11 lb ft).

4. Start the engine. Inspect for CNG fuel leaks at each serviced fitting using the J 41416 Ultrasonic Leak Detector.