2010 Cadillac CTS Sedan AWD V6-3.0L Page 1935
The heated oxygen sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding
air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an Open Loop mode, ignoring the
HO2S signal voltage while calculating the air-to-fuel ratio. While the engine runs, the HO2S heats up and begins to generate a voltage within a
range of 0-1,275 mV. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module
uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases toward 1,000 mV indicates a rich fuel mixture. An HO2S
voltage that decreases toward 0 mV indicates a lean fuel mixture.
The heating elements inside each HO2S heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed
Loop earlier and the control module to calculate the air-to-fuel ratio sooner.
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 voltage is between 10-32 V.
* The engine speed is between 1,225-2,100 RPM.
* The mass air flow (MAF) is between 4-13 g/s.
* The vehicle speed is between 64-125 km/h (40-78 mph).
* The fuel level is greater than 10 %.
* The fuel system is in Closed Loop.
* The predicted catalytic converter temperature is between 615-980掳C (1,139-1,796掳F).
* The HO2S heater is ON for more than 180 s.
* 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 100 mV before accumulated mass air flow exceeds 36 grams.
P2273
The ECM does not detect an HO2S voltage less than 100 mV before the accumulated mass air flow exceeds 36 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 (LLT) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)Engine Controls Schematics
(LF1) (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/Circuit Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)
* Heated Oxygen Sensor Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/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
