P2271-O2 SENSOR 1/2 SIGNAL STUCK RICH





For a complete wiring diagram Refer to Section 8W.


  • When Monitored:

    O2 Sensor Heater Temperature is greater than 496°C (925°F) and battery voltage greater than 10.99 volts.

  • Set Condition:

    The Oxygen Sensor voltage is stuck rich for a calibrated amount of time. One Trip Fault. Three good trips to turn off the MIL.


Possible Causes
 
(K141) O2 1/2 SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
 
(K904) O2 RETURN DOWNSTREAM CIRCUIT SHORTED TO BATTERY VOLTAGE
 
(K141) O2 1/2 SIGNAL CIRCUIT OPEN
 
(K904) O2 RETURN DOWNSTREAM CIRCUIT OPEN
 
O2 SENSOR
 
PCM
 


Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).



Diagnostic Test

1.O2 SENSOR ABOVE 3.7 VOLTS

NOTE: When only one O2 Sensor is shorted to voltage, the scan tool will display all O2 Sensor voltage readings at approximately 5.0 volts. When diagnosing this DTC, only diagnose the O2 Sensor that set the DTC.






Is the voltage above 3.7 volts?

Yes
  • Go To 2


No

2.(K141) O2 1/2 SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE






NOTE: Measure the voltage in reference to ground, not the (K904) O2 Return Downstream circuit.



Is the voltage above 0 volts?

Yes


No
  • Go To 3

3.(K904) O2 RETURN DOWNSTREAM CIRCUIT SHORTED TO BATTERY VOLTAGE








Is there any voltage present?

Yes


No
  • Go To 4

4.O2 SENSOR









Is the voltage between 2.3 and 2.7 volts with the jumper wire installed?

Yes


No
  • Go To 5

    NOTE: Remove the jumper wire before continuing.


5.(K141) O2 1/2 SIGNAL CIRCUIT OPEN





CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.




Is the resistance below 5.0 ohms?

Yes
  • Go To 6


No

6.(K904) O2 RETURN DOWNSTREAM CIRCUIT OPEN





Is the resistance below 5.0 ohms?

Yes
  • Go To 7


No

7.PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.




Were there any problems found?

Yes


No