P2000

P2000-NOX ABSORBER EFFICIENCY BELOW THRESHOLD - BANK 1




For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams.
Theory of Operation

The engine aftertreatment system monitors the O2 content in the diesel engine exhaust. The Engine Control Module (ECM) monitors the exhaust gases for oxygen content and varies the rich/lean fuel mixture of the intake air fuel mixture to adjust system. This diagnostic measures the Oxygen storage capability of the Nitrates of Oxygen (NOx) Absorber Catalyst. The ECM will set the fault if it detects that the NOx Absorber performance is lower than expected. A mobile desoot should not be performed while investigating this fault. The ECM will illuminate the MIL lamp immediately when the diagnostic runs and fails. The ECM will turn off the MIL lamp diagnostic runs and passes in four consecutive drive cycles.

- When Monitored:
This diagnostic will run during deNOx events.

- Set Condition:
The Engine Control Module (ECM) will set the fault if it detects that the NOx Absorber performance is lower than expected.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. OTHER DTCs
1. Ignition on, engine not running.
2. With the scan tool, read DTCs.

Are any other DTCs present?

Yes

- Repair all other DTCs first.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 2

2. MAF SENSOR
1. With the scan tool, read The Mass Air Flow sensor.

Does the Mass Air Flow sensor read 0 ± 2 lb/min?

Yes

- Go To 3

No

- Replace the MAF Sensor.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

3. OPEN CIRCUIT UPSTREAM O2 SENSOR




1. Turn the ignition off.
2. Disconnect the Upstream Oxygen Sensor harness connector.
3. Disconnect the Smart O2 Sensor Module from the Aftertreatment Wiring Harness.

NOTE: Check connectors - Clean/repair as necessary.

4. Measure the resistance of all circuits in the O2 sensor connector to the Smart O2 Sensor Module.





Is the resistance less than 10 Ohms on all circuits?

Yes

- Go To 4

No

- Replace Aftertreatment Wiring Harness.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

4. OPEN CIRCUIT DOWNSTREAM O2 SENSOR




1. Disconnect the Downstream Oxygen sensor harness connector.
2. Disconnect the Smart O2 Sensor Module from the Aftertreatment Wiring Harness.

NOTE: Check connectors - Clean/repair as necessary.

3. Measure the resistance of all circuits in the O2 sensor connector to the Smart O2 Sensor Module.





Is the resistance less than 10 Ohms on all circuits?

Yes

- Go To 5

No

- Replace Aftertreatment Wiring Harness.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

5. OXYGEN SENSORS
1. Remove the Oxygen sensors and inspect for signs of soot.

Is there soot on the oxygen sensors?

Yes

- Using pressurized air, blow out the soot deposits by applying the pressurized air directly into the center hole of the sensors. Reinstall the sensors. Go To 6

No

- Reinstall the sensors. Go To 6

6. EGR LEAK
1. Look for visible signs (soot streaks) of an external EGR leak.

Are there any EGR leaks?

Yes

- Repair the leak.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 7

7. BOOST LEAK
1. Check system for leaks. Perform the INTAKE AIR SYSTEM PRESSURE TEST - DIESEL. Intake Air System Pressure Test.

Is there a leak?

Yes

- Repair the leak.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 8

8. EXHAUST LEAKS
1. Perform the CHECKING THE EXHAUST SYSTEM FOR LEAKS TEST - DIESEL. Checking the Exhaust System For Leaks.

Is there any leaks?

Yes

- Repair the Exhaust system leaks.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.