2010 Cadillac CTS Sedan AWD V6-3.0L Page 1934
4. Ignition OFF, connect a 3 A fused jumper wire between the high signal circuit terminal B and the low signal circuit terminal A.
Note: The low signal circuit is tied to a pull-up circuit within the ECM. A voltage of 0.90-1.10 V on the low signal circuit is normal.
5. Ignition ON, verify the scan tool HO2S parameter displays 0.0 V.
瀚慖f greater than the specified range, test the low signal circuit for an open/high resistance or for a short to voltage. If the circuit tests
normal, replace the K20 ECM.
6. If all circuits test normal, test or replace the appropriate B52 HO2S.
Repair Instructions
Caution: Refer to Heated Oxygen Sensor Resistance Learn Reset Caution (See: Powertrain Management/Computers and Control
Systems/Oxygen Sensor/Service Precautions/Heated Oxygen Sensor Resistance Learn Reset Caution).
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LF1) (See: Powertrain Management/Computers and Control Systems/Oxygen
Sensor/Service and Repair)Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LLT) (See: Powertrain Management/Computers and
Control Systems/Oxygen Sensor/Service and Repair)
* Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LF1) (See: Powertrain Management/Computers and Control Systems/Oxygen
Sensor/Service and Repair)Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LLT) (See: Powertrain Management/Computers and
Control Systems/Oxygen Sensor/Service and Repair)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup, and programming
P2271
DTC P2271 or P2273 (w/LF1)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P2271
- HO2S Signal Stuck Rich Bank 1 Sensor 2
DTC P2273
- HO2S Signal Stuck Rich Bank 2 Sensor 2
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
