2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 2634
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
1. Ignition ON, observe the DTC information with a scan tool. Verify that no B52 HO2S heater DTCs are set.
瀚慖f any B52 HO2S heater DTCs are set, perform those diagnostics first. Refer to Diagnostic Trouble Code (DTC) List - Vehicle (See:
Diagnostic Trouble Code Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle).
2. Engine idling, move the appropriate B52 HO2S 2 harness connector and the engine control module (ECM) harness connector while
monitoring the B52 HO2S 2 voltage parameter with a scan tool. Verify that the B52 HO2S parameter does not change abruptly while moving
the related harnesses.
瀚慖f the B52 HO2S parameter does change abruptly while moving the related harnesses repair the circuit as necessary.
3. Engine idling at operating temperature, observe the appropriate B52 HO2S 2 parameter with a scan tool. Verify the following:
* The B52 HO2S 1 value should vary from below 200 mV to above 800 mV and respond to fueling changes.
* The B52 HO2S 2 should fluctuate at less than 380 mV or greater than 520 mV. The values should not remain within 380 mV and 520
mV.
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
Note: All modules must be powered down or misdiagnosis may result.
1. Ignition OFF, disconnect the harness connector at the appropriate B52 HO2S.
