Tools Required

J 45878 Combustible Gas Detector

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 .

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. Disconnect the fuel rail temperature (FRT) sensor (2) electrical connector.



4. Support the fuel rail flange (3) with a back-up wrench (2) while loosening the sensor with another wrench (1).
5. Remove the sensor and discard the O-ring if re-installing the sensor.

Caution: Natural gas is stored under high pressure. If a leak occurs, the high pressure could cause a personal injury. In order to prevent Compressed Natural Gas (CNG) fuel leaks, always replace the CNG fuel system O-rings during service.

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. Loosely install the FRT sensor (2) with a new O-ring (3). Lubricate the O-ring with petroleum jelly or the equivalent.



2. Support the fuel rail flange (3) with a back-up wrench (2) while tightening the sensor with a crowfoot and torque-wrench.

Tighten
Tighten the FRT sensor to 9 N·m (7 lb ft).

3. Connect the FRT sensor electrical connector.
4. Connect the negative battery cable.

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

5. Start the vehicle. Inspect for CNG fuel leaks at each serviced fitting using the J 45878 .