2010 Cadillac CTS Sedan AWD V6-3.6L Page 1930
* An HO2S will not cause this DTC to set without the occurrence of circuit related HO2S DTCs. Do not replace an HO2S to address this DTC.
* Observing the LT FT Bn 1 and Bn 2 parameters, while driving the vehicle can determine whether the lean condition is effecting only one
bank , or is common to both banks of the engine.
* A fuel system delivery condition causes this DTC to set. Thoroughly inspect all items that cause a lean condition. Refer to Fuel System
Diagnosis (See: Powertrain Management/Computers and Control Systems/Testing and Inspection/Component Tests and General
Diagnostics/Fuel System Diagnosis).
* Any un-metered air into the engine causes this DTC to set. Thoroughly inspect all areas of the engine for vacuum leaks.
* A MAF sensor condition can cause this DTC without setting a MAF DTC. If there is a MAF sensor condition, the MAF sensor parameters
will appear to be within range.
* Inspect the air filter for being the correct one for this application. Make sure that the engine oil fill cap is in place and that it is tight. Verify
that the engine oil dip stick is fully seated.
Reference Information
Schematic Reference
Engine Controls Schematics (LLT) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)Engine Controls Schematics
(LF1) (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/Circuit Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/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. Observe the DTC information with a scan tool. DTC P2177, P2179, P2187, or P2189 should not be set.
瀚慖f any other DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code Descriptions/Diagnostic
Trouble Code (DTC) List - Vehicle) to diagnosis the applicable DTC.
2. Ignition ON, observe the barometric pressure (BARO) sensor pressure parameter and compare the reading on the scan tool to the barometric
pressure table. Refer to Altitude Versus Barometric Pressure (See: Powertrain Management/Computers and Control Systems/Specifications
).
瀚慖f the BARO sensor pressure is not within the range specified for your altitude, refer to DTC P2227, P2228, or P2229 (LLT) ( See: P
Code Charts/P2227).
3. Engine at normal operating temperature, observe the scan tool Long Term Fuel Trim parameters. The LT FT Cruise/Accel parameters should
be less than 33 %. The LT FT Idle/Decel parameters should be less than 7 %.
瀚慖f not within the specified range, verify none of the following conditions exist:
* The heated oxygen sensor (HO2S) is installed securely and the electrical connector is not contacting the exhaust system.
* Missing, restricted, or leaking exhaust components-Refer to Symptoms - Engine Exhaust (See: Engine, Cooling and Exhaust/Exhaust
System/Testing and Inspection/Symptoms - Engine Exhaust).
* The air intake system after the MAF sensor for vacuum leaks
* A mass air flow (MAF) sensor signal that is skewed-If the Short Term FT parameters for both banks changes greater than 20 % when the
MAF sensor is disconnected, refer to DTC P0101 (w/LLT) (See: P Code Charts/P0101)DTC P0101 (LF1) (See: P Code Charts/P0101).
* Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) (See: Powertrain Management/Computers
and Control Systems/Testing and Inspection/Component Tests and General Diagnostics/Alcohol/Contaminants-in-Fuel Diagnosis (with
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)) and Fuel System Cleaning (See: Powertrain Management/Fuel Delivery and Air Induction/Service and Repair).
* Splits, kinks, or improper connections at the vacuum hoses
* The fuel system is operating lean. Refer to Fuel System Diagnosis (See: Powertrain Management/Computers and Control
