2010 Cadillac CTS Sedan AWD V6-3.0L Page 1900

2010 Cadillac CTS Sedan AWD V6-3.0L Page 1900

* 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

Systems/Testing and Inspection/Component Tests and General Diagnostics/Fuel System Diagnosis).

* Vacuum leaks at the intake manifold or throttle body

* Leaking crankcase ventilation system

* The engine control module grounds for being clean, tight, and in the correct locations

* A high engine oil level condition-A high engine oil level causes oil residue to form on the mass air flow (MAF) sensor, causing a lean

indication. The MAF sensor does not need to be replaced.

* Vacuum leaks that only affect one bank of the engine-For example, the intake manifold, the injector O-rings.

* Lean injectors-Refer to Fuel Injector Solenoid Coil Test (w/LLT) (See: Powertrain Management/Computers and Control

Systems/Testing and Inspection/Component Tests and General Diagnostics/Fuel Injector Solenoid Coil Test)Fuel Injector Solenoid Coil

Test (w/LF1) (See: Powertrain Management/Fuel Delivery and Air Induction/Fuel Injector/Testing and Inspection).

* 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).

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.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

P2178

DTC P2178, P2180, P2188, or P2190 (w/LLT)

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 P2178

- Fuel Trim System Rich at Cruise or Acceleration Bank 1

DTC P2180

- Fuel Trim System Rich at Cruise or Acceleration Bank 2

DTC P2188

- Fuel Trim System Rich at Idle Bank 1

DTC P2190

- Fuel Trim System Rich at Idle Bank 2

Circuit Description

The fuel trim control system monitors the range of the air/fuel ratio in order to maintain the desired ratio for optimum emissions performance. The

system performs tests during certain operating conditions to detect unmetered air or unmetered fuel. The fuel trim control system operation can be

observed by monitoring the scan tool Short Term and Long Term Fuel Trim parameters.

Conditions for Running the DTC