air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. Heating
elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The control module supplies the HO2S with a
reference, or bias, voltage of about 450 mV. When the engine is first started, the control module operates in Open Loop, ignoring the HO2S voltage
signal. Once the HO2S reaches operating temperature and Closed Loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV
that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream. Low HO2S voltage indicates a lean exhaust
stream.
Conditions for Running the DTC
* Before the ECM can report DTC P2271, or P2273 failed, DTCs P013A, P013C, P013E, P014A, P2270, and P2272 must run and pass.
* DTCs P0036, P0037, P0038, P0137, P0138, P0140, P0141, P0443, P0458, P0459, P2232 are not set.
* The ignition 1 voltage is between 10-18 volts.
* The engine speed is between 500-5,000 RPM.
* The mass air flow (MAF) is between 3-50 g/s.
* The vehicle speed is between 24-132 km/h (15-82 mph).
* The fuel level is greater than 10 percent.
* The fuel system is in Closed Loop.
* The engine run time is equal to or more than 5 minutes.
* The accelerator pedal position (APP) is steady.
* The torque converter clutch is TCC is applied.
* The DTCs run once per ignition cycle, during decel fuel cut-off, when the above conditions are met.
Conditions for Setting the DTC
P2271
The ECM does not detect an HO2S voltage less than 150 mV before accumulated mass air flow exceeds 550 grams.
P2273
The ECM does not detect an HO2S voltage less than 100 mV before the accumulated mass air flow exceeds 76 grams.
Action Taken When the DTC Sets
DTCs P2271 or P2273 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P2271 or P2273 are Type B DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
* Heated Oxygen Sensor Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical
Diagnostic Procedures/Wiring Repairs/Heated Oxygen Sensor Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
