P2272
DTC P2270 or P2272
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC P2270
- HO2S Signal Stuck Lean Bank 1 Sensor 2
DTC P2272
- HO2S Signal Stuck Lean Bank 2 Sensor 2
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
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
* DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0116, P0117, P0118, P0125, P0128, P0171, P0172, P0174, P0175, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0606, P1516, P2101, P2135, P2176 are not set.
* The ignition voltage is between 10-32 volts.
* The engine speed is between 900-2,500 RPM.
* The mass air flow (MAF) is between 3-20 g/s.
* The vehicle speed is between 70-130 km/h (43.5-80.8 mph).
* The fuel level is greater than 10 percent.
* The fuel system is in Closed Loop.
* The catalytic converter temperature is between 550-900°C (1,022-1,652°F).
* The DTCs run once per ignition cycle when the above conditions are met. DTCs are allowed to run more than once per ignition cycle after a code clear or an ECM reflash.
Conditions for Setting the DTC
The ECM does not detect an HO2S Sensor 2 voltage greater than 791 mV before accumulated mass air flow exceeds 160 grams.
Action Taken When the DTC Sets
DTCs P2270 and P2272 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P2270 and P2272 are Type B DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics (LZ1) [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Connector Views
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition OFF, open the hood to disable the Auto-Stop function. Refer to Hybrid Modes of Operation Description Hybrid Modes of Operation Description.
2. Ignition ON, verify the scan tool hood position parameter displays Open.
• If the hood position does not display Open, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle for DTC P254F.
3. Ignition ON, observe the DTC information with a scan tool. Verify that no HO2S heater DTCs are set.
• If any HO2S heater DTCs are set, perform those diagnostics first. Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.
4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, open the hood to disable the Auto-Stop function.
2. Disconnect the harness connector at the appropriate HO2S.
3. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 ohm between the low reference circuit terminal A and ground.
• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
4. Ignition ON, verify the appropriate scan tool HO2S parameter is approximately 450 mV.
• If less than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
• If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
5. Ignition ON, install a 3 A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool HO2S parameter is less than 60 mV.
• If greater than the specified range, test the signal circuit for an open/high resistance. If the circuits test normal, replace the ECM.
6. Verify none of the following conditions exist:
* Lean fuel injectors-Refer to Fuel Injector Diagnosis (CH47976) Fuel Injector Diagnosis (J39021 or Scan Tool)
* Water intrusion in the HO2S harness connector
* Low fuel system pressure-Refer to Fuel System Diagnosis.
* Fuel that is contaminated-Refer to Alcohol/Contaminants-in-Fuel Diagnosis Testing and Inspection
* Exhaust system leaks-Refer to Exhaust Leakage Exhaust Leakage.
* Engine vacuum leaks
* Contaminated HO2S - Silicon
* An engine mechanical condition- Symptoms - Engine Mechanical Symptoms - Engine Mechanical
• If you find any of the above conditions, repair as necessary.
7. If all circuits test normal, replace the appropriate HO2S.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (2500 Series) Service and RepairHeated Oxygen Sensor Replacement - Bank 1 Sensor 2 (1500 Series) Service and Repair
* Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (2500 Series) Service and RepairHeated Oxygen Sensor Replacement - Bank 2 Sensor 2 (1500 Series) Service and Repair
* Perform the scan tool Heated Oxygen Sensor Resistance Learn Reset after replacing a HO2S.
* Control Module References Control Module References for ECM replacement, , programming and setup.