Diagnostic Test

1. Start the engine.
2. Allow the engine to reach normal operating temperature.
3. With a scan tool, select View DTCs.
   NOTE:

   It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.

   Is the DTC Active or Pending at this time?

   Yes 

   • Go To  2

   No 

   • Perform the INTERMITTENT DTC diagnostic procedure. Refer to CHECKING FOR AN INTERMITTENT DTC .

1. Turn the ignition off.
   WARNING:

   The normal operating temperature of the exhaust system is very high. Never work around or attempt to service any part of the exhaust system until it has cooled. Special care should be taken when working near the catalytic converter. The temperature of the converter rises to a high level after a short period of engine operating time.

2. Connect Exhaust Cone (special tool #8404-ECT, Exhaust Cone, Truck) to Air Pressure Regulator (with hose) #W-18-MIL-1146AS.
   CAUTION:

   The air pressure must not exceed 27.6 kPa (4 psi), otherwise engine damage can occur.

3. Attach shop air to the air pressure regulator.
4. Adjust the Air Pressure Regulator to 27.6 kPa (4 psi)
5. Insert the exhaust cone into the vehicle tail pipe.
6. If the vehicle is equipped with dual exhaust. Use the plug one side of the dual exhaust pipe. Pressurize the other as described above.
7. Apply SNOOP leak finder liquid or a mixture of liquid dish soap and water 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.
8. Use the following definitions to help determine if system or component repair/replacement is necessary:
9. Type 1 Leak  is defined as a leak where very small foam like bubbles 1 mm (0.04 of an inch) or less appear.
10. 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.
11. Type 2 Leak  is defined as a leak where larger bubbles pea size, 8 mm (0.3 of an inch) or greater appear.
12. 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

13. If a leak is found that matches the above definition, repair or replace the component as necessary.
14. 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 PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

    No 

    • Go To  3

1. Turn the ignition off
2. Disconnect the O2 Sensor 2/1 harness connector.
3. Ignition on, engine not running.
4. Measure the voltage on the (K43) O2 2/1 Signal circuit in the O2 Sensor harness connector.

   Is the voltage between 4.5 and 5.0 volts?

   Yes 

   • Go To  4

   No 

   • Check the (K43) O2 2/1 Signal circuit for a short to ground, open, or short to voltage. If OK, replace and program the Powertrain Control Module in accordance with the Service Information.
   • Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

1. Measure the voltage on the (K906) O2 2/1 Return circuit in the O2 Sensor harness connector.

   Is the voltage at 2.5 volts?

   Yes 

   • Go To  5

   No 

   • Check the (K906) O2 2/1 Return circuit for a short to ground, open, or short to voltage. If OK, replace and program the Powertrain Control Module in accordance with the Service Information.
   • Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

Repair 

• Replace the O2 Sensor.
• Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .