P2A00

P2A00-O2 SENSOR 1/1 CIRCUIT PERFORMANCE




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 exhaust. The Engine Control Module (ECM) monitors the exhaust gases for oxygen content and varies the fuel injector on time to control the intake air fuel mixture. This monitor checks to make sure that the O2 content matches the expected O2 content for the engine operating conditions. The ECM will set the fault if it detects that the actual O2 measurement does not match the expected value. 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 monitor runs when the engine is running.

- Set Condition:
The Engine Control Module (ECM) will set the fault if it detects that the actual O2 measurement does not match the expected value.





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

NOTE: Before replacing O2 Sensor or O2 Sensor Module, check aftertreatment wiring harness for spread terminals. For wiring harness checking procedure, DO NOT back probe, use Miller Tool Kit 8197A (6801 Tool).

1. ACTIVE DTC
1. Turn the ignition on.
2. With the scan tool, record all Freeze frame data.
3. With the scan tool, erase DTCs.
4. Turn the ignition off for 30 seconds.
5. Start the engine and let idle up to five minutes.
6. With the scan tool, read DTCs.

Did the DTC reset?

Yes

- Go To 2

No

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

2. (K89) O2 SENSOR 1/1 PUMP CURRENT CIRCUIT SHORTED TO VOLTAGE




1. Turn the ignition off.
2. Disconnect the O2 Sensor Module harness connector.

NOTE: Check connectors - Clean/repair as necessary.

3. Turn the ignition on.
4. Measure the voltage on the (K89) 02 Sensor 1/1 Pump Current circuit at the O2 Sensor Module harness connector.

Is there any voltage present?

Yes

- Repair the short to voltage in the (K89) 02 Sensor 1/1 Pump Current circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 3

3. (K89) O2 SENSOR 1/1 PUMP CURRENT CIRCUIT SHORTED TO GROUND




1. Disconnect the 02 Sensor 1/1 harness connector.

NOTE: Check connectors - Clean/repair as necessary.

2. Measure resistance between ground and the (K89) 02 Sensor 1/1 Pump Current circuit at the O2 Sensor Module harness connector.

Is the resistance below 10k Ohms?

Yes

- Repair the short to ground in the (K89) 02 Sensor 1/1Pump Current circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 4

4. (K89) O2 SENSOR 1/1 PUMP CURRENT CIRCUIT OPEN




1. Measure the resistance of the (K89) 02 Sensor 1/1 Pump Current circuit between the 02 Sensor 1/1 harness connector and the O2 Sensor Module harness connector.

Is the resistance less than 10.0 Ohms?

Yes

- Go To 5

No

- Repair the open or high resistance in the (K89) 02 Sensor 1/1 Pump Current circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

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

Are there any EGR leaks?

Yes

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

No

- Go To 6

6. EXHAUST SYSTEM LEAK
1. Perform the CHECKING THE EXHAUST SYSTEM FOR LEAKS test procedure. Checking the Exhaust System For Leaks

Were any exhaust leaks found?

Yes

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

No

- Go To 7

7. O2 SENSOR 1/1

NOTE: Excessive soot build up can be caused by over fueling. If excessive soot build up is present, the fuel system operation should be checked and both of the O2 sensors should be cleaned.

1. Remove the O2 Sensors.
2. Clean the soot from the O2 Sensors.
3. Reinstall the O2 Sensors.
4. Turn the ignition on.
5. With the scan tool, erase DTCs.
6. Start the engine and let idle up to five minutes.
7. With the scan tool, read DTCs.

Did the DTC reset?

Yes

- Replace the O2 Sensor 1/1.
- Go To 8

No

- Go To 8

8. O2 SENSOR MODULE
1. Turn the ignition on.
2. With the scan tool, erase DTCs.
3. Start the engine and let idle up to five minutes.
4. With the scan tool, read DTCs.

Did the DTC reset?

Yes

- Replace the O2 Sensor Module.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

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