2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1870
* Lean fuel injectors-Refer to Fuel Injector Solenoid Coil Test (LAU) (See: Powertrain Management/Fuel Delivery and Air
Induction/Fuel Injector/Testing and Inspection/Fuel Injector Solenoid Coil Test)Fuel Injector Solenoid Coil Test (LF1, LFW) (See:
Powertrain Management/Fuel Delivery and Air Induction/Fuel Injector/Testing and Inspection/Fuel Injector Solenoid Coil Test).
* Water intrusion in the HO2S harness connector
* Low fuel system pressure-Refer to Fuel System Diagnosis (LF1 China) (See: Powertrain Management/Fuel Delivery and Air
Induction/Fuel Pump/Testing and Inspection/Fuel System Diagnosis (China))Fuel System Diagnosis (LF1 Except China) (See:
Powertrain Management/Fuel Delivery and Air Induction/Fuel Pump/Testing and Inspection/Fuel System Diagnosis (Except China))Fuel
System Diagnosis (LAU China) (See: Powertrain Management/Fuel Delivery and Air Induction/Fuel Pump/Testing and Inspection/Fuel
System Diagnosis (China))Fuel System Diagnosis (LAU Except China) (See: Powertrain Management/Fuel Delivery and Air
Induction/Fuel Pump/Testing and Inspection/Fuel System Diagnosis (Except China)).
* Fuel that is contaminated-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool) (See: Powertrain Management/Fuel Delivery
and Air Induction/Fuel/Testing and Inspection/Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool))Alcohol/Contaminants-in-Fuel
Diagnosis (Without Special Tool) (See: Powertrain Management/Computers and Control Systems/Testing and Inspection/Component
Tests and General Diagnostics/Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)).
* The vacuum hoses for splits, kinks, and proper connection
* The air intake system after the mass air flow sensor for vacuum leaks
* Exhaust system leaks
* Contaminated HO2S - Silicon
* An engine mechanical condition-Refer to Symptoms - Engine Mechanical (See: Engine, Cooling and Exhaust/Engine/Testing and
Inspection/Symptom Related Diagnostic Procedures/Symptoms - Engine Mechanical).
瀚慖f you find any of the above conditions, repair as necessary.
5. If all circuits/connections test normal, replace the B52 HO2S 2.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Heated Oxygen Sensor Replacement - Sensor 2 (LAU) (See: Powertrain Management/Computers and Control Systems/Oxygen
Sensor/Service and Repair/Heated Oxygen Sensor Replacement - Sensor 2)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for engine control module replacement, setup, and
programming
P2271
DTC P2271 (Without 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 Descriptor
DTC P2271
- HO2S Signal Stuck Rich Sensor 2
Circuit Description
The engine control module (ECM) supplies a voltage near 450 mV between the heated oxygen sensor (HO2S) high signal circuit and the low
reference circuit. The HO2S varies the voltage over a range from about 1,000 mV when the exhaust is rich, down through about 10 mV when the
exhaust is lean. The ECM monitors and stores the HO2S voltage information. The ECM evaluates the HO2S voltage samples in order to determine
the amount of time that the HO2S voltage was out of range. The ECM compares the stored HO2S voltage samples taken within each sample period
and determines if the majority of the samples are out of the operating range. The ECM test for the following conditions:
* The ECM monitors the HO2S voltage to determine if the signal voltage goes below a predetermined threshold within a certain amount of
time. If the ECM determines that the signal voltage remains above the threshold, the ECM will command the fuel system lean to determine if
the HO2S signal voltage can be forced below the threshold within a certain amount of time.
* The ECM monitors the HO2S voltage during fuel cut-off to determine if the signal voltage is greater than a predetermined threshold.
Conditions for Running the DTC
* Before the ECM can report DTC P2270 failed, DTCs P0036, P0037, P0038, P0137, P0138, P0140, P0141, P0341, P0342, P0343, P0346,
P0347, P0348, P0366, P0367, P0368, P0391, P0392, P0393, P0443, P0458, and P0459 must run and pass.
