P2271

P2271 - O2 Sensor 1/2 Signal Stuck Rich






For wiring diagrams, refer to.

• When Monitored: With the engine running, the odometer greater than the minimum mileage allowable for catalyst break-in, and no global or monitor conflicts or disabling conditions present. The test will only run if the monitor has not already run and passed or failed.

• Set Condition: The PCM detects that the sensor does not output a voltage greater than a calibrated high voltage value and less than a calibrated low voltage value within a specific time period. If the voltage pass values are not achieved after the total accumulated test time, a pending fault will be set. An active fault is matured on a second trip failure. Three good trips will turn off the MIL.






• Always perform the pre-diagnostic troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics. Pre-Diagnostic Troubleshooting Procedure

Test Step 1 - DTC is Active

• Start the engine and allow it to reach operating temperature.


When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

• It may be necessary to test drive the vehicle within the DTC monitoring conditions in order for this DTC to set.

• With a scan tool, select view DTCs.

Is the status active for this DTC?

Yes

• Go to Test Step 2 => [ Test
Step 2 - Checking the Exhaust System for Leaks ]

No

• Refer to the checking for an intermittent DTC diagnostic procedure. Refer to => Non-DTC Based Diagnostics. Checking for an Intermittent DTC

Test Step 2 - Checking the Exhaust System for Leaks

• Perform the diagnostic procedure for Checking the Exhaust System For Leaks. Refer to => Non-DTC Based Diagnostics.

Were any problems found?

Yes

• Repair as necessary.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Go to Test Step 3 => [ Test
Step 3 - Checking the Oxygen Sensor Operation ]

Test Step 3 - Checking the Oxygen Sensor Operation

• Check for signs of contaminants that may have damaged the O2 sensor, such as contaminated fuel, unapproved silicone, oil and coolant.

• Perform the diagnostic procedure for Checking the Oxygen Sensor Operation. Refer to => Non-DTC Based Diagnostics. Testing and Inspection

Were any problems found?

Yes

• Repair as necessary.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Go to Test Step 4 => [ Test
Step 4 - PCM ]

Test Step 4 - PCM

• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the 1/2 O2 sensor and the PCM.

• Look for any chafed, pierced, pinched, or partially broken wires.

• Look for broken, bent, pushed out or corroded terminals.

• Refer to any technical service bulletins that may apply.

Were any problems found?

Yes

• Repair as necessary.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Replace and program the PCM.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test