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
Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding 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 0-1,275 mV that fluctuates above and below the bias voltage. A high HO2S voltage indicates a rich exhaust stream. A low HO2S voltage indicates a lean exhaust stream.
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
* DTC P0036, P0037, P0038, P0137, P0138, P0140, P0141, P0443, P0458, P0459 or P2232 is not set.
* The ignition voltage is between 10-32 volts.
* The engine run time is greater than 5 minutes.
* The engine speed is between 1,000-2,550 RPM.
* The mass air flow (MAF) is between 3-20 g/s.
* The vehicle speed is between 71-120 km/h (44-75 mph).
* Evap is not in control of purge.
* HO2S heater is on for greater than 100 s.
* Power Take Off Mode is not active.
* EGR Intrusive diagnostic is not active.
* The fuel level is greater than 10 percent.
* The fuel system is in Closed Loop.
* The catalytic converter temperature is between 600-900°C (1,112-1,652°F).
* The DTCs run once per ignition cycle when the above conditions are met.
Conditions for Setting the DTC
P2270
The ECM does not detect a HO2S voltage greater than 805 mV before accumulated mass air flow exceeds a calibrated value.
P2272
The ECM does not detect a HO2S voltage greater than 775 mV before the accumulated mass air flow exceeds a calibrated value.
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 [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Connector End Views By Name
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 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.
2. Engine running, observe the appropriate scan tool HO2S Bank 1 or 2 Sensor 1 or 2 voltage parameter. The reading should be within the range of 50-1,050 mV.
3. Move the related wiring and connectors while observing the HO2S Heater parameter with a scan tool. The parameter should not change with movement.
• If movement affects the parameter, repair the appropriate harness or connector.
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 and all vehicle systems OFF, disconnect the harness connector at the appropriate B52 Heated Oxygen Sensor. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 5 ohms 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.
3. Ignition ON, verify the appropriate scan tool B52 HO2S voltage 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 K20 Engine Control Module.
• If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
4. Install a 3 A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool HO2S voltage 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 K20 Engine Control Module.
5. Verify none of the following conditions exist:
* Lean fuel injectors-Refer to Fuel Injector Diagnosis (CH47976) Fuel Injector Diagnosis (CH47976)Fuel Injector Diagnosis (J39021 or Scan Tool) Fuel Injector Diagnosis (J39021 or Scan Tool)
* Water intrusion in the HO2S harness connector
* Low fuel system pressure-Refer to Fuel System Diagnosis (Without FPCM) Component Tests and General DiagnosticsFuel System Diagnosis (FPCM) Component Tests and General Diagnostics
* Fuel that is contaminated-Refer to Alcohol/Contaminants-in-Fuel Diagnosis Alcohol/Contaminants-in-Fuel Diagnosis
* Exhaust leaks
* 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.
6. If all circuits test normal, replace the appropriate B52 Heated Oxygen Sensor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (1500 Series) Service and RepairHeated Oxygen Sensor Replacement - Bank 1 Sensor 2 (2500 Series) Service and Repair
* Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (1500 Series) Service and RepairHeated Oxygen Sensor Replacement - Bank 2 Sensor 2 (2500 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.