Test Step 2 - CHECKING THE EXHAUST SYSTEM FOR LEAKS

• Turn the ignition off.
• Raise the vehicle in accordance with the Service Information.

• Connect the Exhaust Cone to the Air Pressure Regulator (with hose) W-18-MIL-1146AS.

• Attach shop air to the air pressure regulator.
• Adjust the Air Pressure Regulator to 27.6 kPa (4 psi).
• Insert the exhaust cone into the vehicle tail pipe.
• If the vehicle is equipped with dual exhaust. Use the Exhaust Cone, Truck with equipped attached plug, plug one side of the dual exhaust pipe. Pressurize the other as described above.
• Apply Air Leak Detector (or an equivalent leak finder liquid) to the following areas:
• All welded joints from the exhaust manifold to 152.4 mm (6 inches) behind the downstream O2 Sensor
• O2 Sensor seal points
• O2 Sensor boss welds
• Flange/joint connection(s)
• Exhaust manifold to cylinder head connection(s)
• EGR solenoid gasket base and tube seal points (if equipped)
• Watch for the liquid/soapy water to bubble.
• Use the following definitions to help determine if system or component repair/replacement is necessary:

>>Type 1 Leak<< is defined as a leak where very small foam like bubbles 1 mm (0.04 of an inch) or less appear.

Any Type 1 or greater leaks found in welded joints, O2 Sensor seal points or O2 Sensor boss welds must be repaired or the component must be replaced.

>>Type 2 Leak<< is defined as a leak where larger bubbles pea size, 8 mm (0.3 of an inch) or greater appear.

Any Type 2 or greater leaks found in flange or joint connections, exhaust manifold to cylinder head connections, or EGR gasket and tube seal points must be repaired or the components must be replaced

Leak Location	Repair required if results at 27.6 kPa (4 psi) reveal bubble size:
Welded joints	Type 1, 1 mm (0.04 of an inch) or greater
O2 Sensor seal points	Type 1, 1 mm (0.04 of an inch) or greater
O2 Sensor boss welds	Type 1, 1 mm (0.04 of an inch) or greater
Flange / joint connections	Type 2, 8 mm (0.3 of an inch) or greater
Exhaust Manifold to cylinder head connections	Type 2, 8 mm (0.3 of an inch) or greater
EGR gasket and tube seal points	Type 2, 8 mm (0.3 of an inch) or greater

• If a leak is found that matches the above definition, repair or replace the component as necessary.
• Once the repair is complete, repeat the procedure to verify that all leaks have been repaired.

Were any exhaust leaks found?

Yes

• Repair or replace the leaking exhaust parts as necessary.
• Perform the Powertrain Verification Test. Refer to Engine .

No

• Go to Test Step 3 - (K99) O2 SENSOR 1/1 SIGNAL CIRCUIT