2010 Cadillac Truck SRX FWD V6-3.0L Page 1403

2010 Cadillac Truck SRX FWD V6-3.0L Page 1403

* Vacuum hose splits, kinks, and incorrect connections

* Engine vacuum leaks

* Crankcase ventilation system for vacuum leaks

* Fuel pressure that is too low or too high-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)).

* Contaminated Fuel-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)).

* Exhaust system restrictions

瀚慖f you find any of the above conditions, repair as necessary.

2. Ignition OFF, remove the T8 ignition coil of the misfiring cylinder, but leave the electrical connector connected.

3. Inspect the ignition coil boot for the following conditions:

* Holes

* Tears

* Carbon tracking

* Oil contamination

* water intrusion

瀚慖f you find any of the above conditions, repair as necessary.

4. Install the J 26792 - Spark Tester to the boot of the appropriate T8 ignition coil and ground.

Note: An erratic or weak spark is considered a no spark condition.

5. Attempt to start the engine and observe the J 26792 - Spark Tester. The spark tester should spark.

瀚慖f there is no spark, refer to Electronic Ignition System Diagnosis (See: Powertrain Management/Computers and Control

Systems/Testing and Inspection/Component Tests and General Diagnostics/Electronic Ignition System Diagnosis) for diagnosis of the

ignition coil.

6. Ignition OFF, remove the spark plug from the misfiring cylinder. Verify that the spark plug does not exhibit the following conditions:

* Gas, coolant, or oil fouled-Refer to Spark Plug Inspection (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine Performance

Checks/Spark Plug/Testing and Inspection).

* Cracked, worn, incorrectly gapped-Refer to Ignition System Specifications (LAU) (See: Powertrain Management/Ignition

System/Specifications)Ignition System Specifications (LF1) (See: Powertrain Management/Ignition System/Specifications).

瀚慖f there is a condition with the spark plug, replace the spark plug.

7. Exchange the suspected spark plug with another cylinder that is operating correctly.

8. Engine idling, observe the scan tool Misfire Current Counter parameters. The misfire should not follow the spark plug exchange.

瀚慖f the misfire follows the spark plug, replace the spark plug.

9. If all conditions test normal, test or inspect for the following:

* A lean or rich Q17 fuel injector-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 (LF1, LFW) (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).

Repair Instructions

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

* Spark Plug Replacement (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine Performance Checks/Spark Plug/Service and

Repair)

* To verify that the performance of the catalytic converter has not been affected by the condition that set this DTC, perform the Repair

Verification for DTC P0420 or P0430. Refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code

Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle) for DTC P0420 or P0430.

2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 1843

2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 1843

* Vacuum hoses for splits, kinks, and improper connections

* Insufficient fuel in the tank

* Low fuel pressure-Refer to Fuel System Diagnosis (w/o FPCM) (See: Powertrain Management/Computers and Control Systems/Testing and

Inspection/Component Tests and General Diagnostics)Fuel System Diagnosis (FPCM) (See: Powertrain Management/Computers and

Control Systems/Testing and Inspection/Component Tests and General Diagnostics).

* Fuel contamination-Refer to 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))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)) for Gasoline or Fuel Composition Diagnosis

(See: Powertrain Management/Computers and Control Systems/Testing and Inspection/Component Tests and General Diagnostics) for E85.

* Malfunctioning fuel injectors-Refer to Symptoms - Engine Exhaust (See: Engine, Cooling and Exhaust/Exhaust System/Testing and

Inspection/Symptoms - Engine Exhaust).

* Missing, loose, or leaking exhaust components from the HO2S forward-Refer to Symptoms - Engine Exhaust (See: Engine, Cooling and

Exhaust/Exhaust System/Testing and Inspection/Symptoms - Engine Exhaust).

* Vacuum leaks at the intake manifold, the throttle body, and the injector O-rings

* The air induction system and the air intake ducts for leaks or for a missing air filter element

* A cracked EVAP canister

* Evaporative pipes obstructed or leaking

* The crankcase ventilation system for leaks

* The HO2S for improper installation and for electrical wires or connectors that may have contacted the exhaust system

* The HO2S signal circuit open, shorted to ground, or shorted to the low reference circuit

* Malfunctioning engine components-Refer to Symptoms - Engine Mechanical (See: Engine, Cooling and Exhaust/Engine/Testing and

Inspection/Symptom Related Diagnostic Procedures/Symptoms - Engine Mechanical).

P0172 or P0175

Allow the engine to reach operating temperature. With the engine running, observe the affected Long Term FT parameter with a scan tool. The

reading should be between -19 and 0 %.

If not within the specified range, inspect for the following:

* With the engine idling and the transmission in the Park or Neutral position, observe the manifold absolute pressure (MAP) sensor parameter.

The MAP sensor parameter should be between 19-42 kPa.

瀚慠efer to DTC P0106 (See: P Code Charts/P0106) if the MAP sensor parameter is not between 19-42 kPa.

* With the engine idling, observe the mass air flow (MAF) sensor parameter. The MAF sensor parameter should be within 2-6 g/s at idle.

瀚慠efer to DTC P0101 or P1101 (See: P Code Charts/P0101) or DTC P0102 or P0103 (See: P Code Charts/P0102) if the MAF sensor

parameter is not within 2-6 g/s at idle.

* Vacuum hoses for splits, kinks, and improper connections

* The air intake duct for being collapsed or restricted

* The air filter for being dirty or restricted

* Objects blocking the throttle body

* Excessive fuel in the crankcase due to leaking fuel injectors

* The evaporative emissions control system for improper operation

* Excessive fuel pressure-Refer to Fuel System Diagnosis (w/o FPCM) (See: Powertrain Management/Computers and Control

Systems/Testing and Inspection/Component Tests and General Diagnostics)Fuel System Diagnosis (FPCM) (See: Powertrain

Management/Computers and Control Systems/Testing and Inspection/Component Tests and General Diagnostics).

* Malfunctioning fuel injectors-Refer to Fuel System Diagnosis (w/o FPCM) (See: Powertrain Management/Computers and Control

Systems/Testing and Inspection/Component Tests and General Diagnostics)Fuel System Diagnosis (FPCM) (See: Powertrain

Management/Computers and Control Systems/Testing and Inspection/Component Tests and General Diagnostics).

* Fuel contamination-Refer to 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))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)).

* The HO2S for improper installation and for electrical wires or connectors that may have contacted the exhaust system

* The HO2S signal circuit shorted to voltage

Repair Instructions

* Air Cleaner Assembly Replacement (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine Performance Checks/Air Cleaner

Housing/Service and Repair)

* Air Cleaner Element Replacement (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine Performance Checks/Air Cleaner

Housing/Air Filter Element/Service and Repair)

* Air Cleaner Resonator Outlet Duct Replacement (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine Performance Checks/Air

Cleaner Housing/Air Cleaner Fresh Air Duct/Hose/Service and Repair/Air Cleaner Resonator Outlet Duct Replacement)

* Evaporative Emission Canister Replacement (1500 Series) (See: Powertrain Management/Emission Control Systems/Evaporative Emissions

2010 Cadillac Truck Escalade RWD V8-6.2L Page 1843

2010 Cadillac Truck Escalade RWD V8-6.2L Page 1843

* Vacuum hoses for splits, kinks, and improper connections

* Insufficient fuel in the tank

* Low fuel pressure-Refer to Fuel System Diagnosis (w/o FPCM) (See: Powertrain Management/Computers and Control Systems/Testing and

Inspection/Component Tests and General Diagnostics)Fuel System Diagnosis (FPCM) (See: Powertrain Management/Computers and

Control Systems/Testing and Inspection/Component Tests and General Diagnostics).

* Fuel contamination-Refer to 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))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)) for Gasoline or Fuel Composition Diagnosis

(See: Powertrain Management/Computers and Control Systems/Testing and Inspection/Component Tests and General Diagnostics) for E85.

* Malfunctioning fuel injectors-Refer to Symptoms - Engine Exhaust (See: Engine, Cooling and Exhaust/Exhaust System/Testing and

Inspection/Symptoms - Engine Exhaust).

* Missing, loose, or leaking exhaust components from the HO2S forward-Refer to Symptoms - Engine Exhaust (See: Engine, Cooling and

Exhaust/Exhaust System/Testing and Inspection/Symptoms - Engine Exhaust).

* Vacuum leaks at the intake manifold, the throttle body, and the injector O-rings

* The air induction system and the air intake ducts for leaks or for a missing air filter element

* A cracked EVAP canister

* Evaporative pipes obstructed or leaking

* The crankcase ventilation system for leaks

* The HO2S for improper installation and for electrical wires or connectors that may have contacted the exhaust system

* The HO2S signal circuit open, shorted to ground, or shorted to the low reference circuit

* Malfunctioning engine components-Refer to Symptoms - Engine Mechanical (See: Engine, Cooling and Exhaust/Engine/Testing and

Inspection/Symptom Related Diagnostic Procedures/Symptoms - Engine Mechanical).

P0172 or P0175

Allow the engine to reach operating temperature. With the engine running, observe the affected Long Term FT parameter with a scan tool. The

reading should be between -19 and 0 %.

If not within the specified range, inspect for the following:

* With the engine idling and the transmission in the Park or Neutral position, observe the manifold absolute pressure (MAP) sensor parameter.

The MAP sensor parameter should be between 19-42 kPa.

瀚慠efer to DTC P0106 (See: P Code Charts/P0106) if the MAP sensor parameter is not between 19-42 kPa.

* With the engine idling, observe the mass air flow (MAF) sensor parameter. The MAF sensor parameter should be within 2-6 g/s at idle.

瀚慠efer to DTC P0101 or P1101 (See: P Code Charts/P0101) or DTC P0102 or P0103 (See: P Code Charts/P0102) if the MAF sensor

parameter is not within 2-6 g/s at idle.

* Vacuum hoses for splits, kinks, and improper connections

* The air intake duct for being collapsed or restricted

* The air filter for being dirty or restricted

* Objects blocking the throttle body

* Excessive fuel in the crankcase due to leaking fuel injectors

* The evaporative emissions control system for improper operation

* Excessive fuel pressure-Refer to Fuel System Diagnosis (w/o FPCM) (See: Powertrain Management/Computers and Control

Systems/Testing and Inspection/Component Tests and General Diagnostics)Fuel System Diagnosis (FPCM) (See: Powertrain

Management/Computers and Control Systems/Testing and Inspection/Component Tests and General Diagnostics).

* Malfunctioning fuel injectors-Refer to Fuel System Diagnosis (w/o FPCM) (See: Powertrain Management/Computers and Control

Systems/Testing and Inspection/Component Tests and General Diagnostics)Fuel System Diagnosis (FPCM) (See: Powertrain

Management/Computers and Control Systems/Testing and Inspection/Component Tests and General Diagnostics).

* Fuel contamination-Refer to 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))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)).

* The HO2S for improper installation and for electrical wires or connectors that may have contacted the exhaust system

* The HO2S signal circuit shorted to voltage

Repair Instructions

* Air Cleaner Assembly Replacement (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine Performance Checks/Air Cleaner

Housing/Service and Repair)

* Air Cleaner Element Replacement (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine Performance Checks/Air Cleaner

Housing/Air Filter Element/Service and Repair)

* Air Cleaner Resonator Outlet Duct Replacement (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine Performance Checks/Air

Cleaner Housing/Air Cleaner Fresh Air Duct/Hose/Service and Repair/Air Cleaner Resonator Outlet Duct Replacement)

* Evaporative Emission Canister Replacement (1500 Series) (See: Powertrain Management/Emission Control Systems/Evaporative Emissions

2010 Cadillac Truck SRX AWD V6-3.0L Page 1403

2010 Cadillac Truck SRX AWD V6-3.0L Page 1403

* Vacuum hose splits, kinks, and incorrect connections

* Engine vacuum leaks

* Crankcase ventilation system for vacuum leaks

* Fuel pressure that is too low or too high-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)).

* Contaminated Fuel-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)).

* Exhaust system restrictions

瀚慖f you find any of the above conditions, repair as necessary.

2. Ignition OFF, remove the T8 ignition coil of the misfiring cylinder, but leave the electrical connector connected.

3. Inspect the ignition coil boot for the following conditions:

* Holes

* Tears

* Carbon tracking

* Oil contamination

* water intrusion

瀚慖f you find any of the above conditions, repair as necessary.

4. Install the J 26792 - Spark Tester to the boot of the appropriate T8 ignition coil and ground.

Note: An erratic or weak spark is considered a no spark condition.

5. Attempt to start the engine and observe the J 26792 - Spark Tester. The spark tester should spark.

瀚慖f there is no spark, refer to Electronic Ignition System Diagnosis (See: Powertrain Management/Computers and Control

Systems/Testing and Inspection/Component Tests and General Diagnostics/Electronic Ignition System Diagnosis) for diagnosis of the

ignition coil.

6. Ignition OFF, remove the spark plug from the misfiring cylinder. Verify that the spark plug does not exhibit the following conditions:

* Gas, coolant, or oil fouled-Refer to Spark Plug Inspection (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine Performance

Checks/Spark Plug/Testing and Inspection).

* Cracked, worn, incorrectly gapped-Refer to Ignition System Specifications (LAU) (See: Powertrain Management/Ignition

System/Specifications)Ignition System Specifications (LF1) (See: Powertrain Management/Ignition System/Specifications).

瀚慖f there is a condition with the spark plug, replace the spark plug.

7. Exchange the suspected spark plug with another cylinder that is operating correctly.

8. Engine idling, observe the scan tool Misfire Current Counter parameters. The misfire should not follow the spark plug exchange.

瀚慖f the misfire follows the spark plug, replace the spark plug.

9. If all conditions test normal, test or inspect for the following:

* A lean or rich Q17 fuel injector-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 (LF1, LFW) (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).

Repair Instructions

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

* Spark Plug Replacement (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine Performance Checks/Spark Plug/Service and

Repair)

* To verify that the performance of the catalytic converter has not been affected by the condition that set this DTC, perform the Repair

Verification for DTC P0420 or P0430. Refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code

Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle) for DTC P0420 or P0430.

2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1847

2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1847

* Splits, kinks, or improper connections at the vacuum hoses.

* The fuel system is operating lean. 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)).

* 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 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 (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).

* 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 heated oxygen sensor (HO2S) is installed securely and the electrical connector is not contacting the exhaust system.

* 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 or P2188

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

DTC P2188

- Fuel Trim System Rich at Idle

Circuit Description

The engine control module (ECM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel

economy, and emission control. Fuel delivery is controlled differently during Open and Closed Loop. During Open Loop, the ECM determines fuel

delivery based on sensor signals without heated oxygen sensor (HO2S) input. During Closed Loop, the HO2S inputs are added and used by the

ECM to calculate short and long term fuel trim fuel delivery adjustments. If the HO2S indicate a lean condition, fuel trim values will be above 0

percent. If the O2S indicate a rich condition, fuel trim values will be below 0 percent. Short term fuel trim values change rapidly in response to the

HO2S signals. Long term fuel trim makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1.

Conditions for Running the DTC

P2178

* Before the ECM can report DTC P2178 failed, DTCs P0008, P0009, P0010, P0011, P0013, P0014, P0016, P0017, P0018, P0019, P0020,

P0021, P0023, P0024, P0101, P0121, P0122, P0123, P0133, P0201, P0202, P0203, P0204, P0205, P0206, P0221, P0222, P0223, P0261,

P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0335, P0336, P0338,

P0443, P0458, P0459, P0461, P0462, P0463, P2068 P2088, P2089, P2090, P2091, P2092, P2093, P2094, and P2095 must run and pass.

* The engine speed is between 1,200-3,400 RPM.

* The mass air flow is between 7-83 grams/second.

* The throttle angle is less than 100 percent.

2010 Cadillac Truck Escalade ESV AWD V8-6.2L Page 1944

2010 Cadillac Truck Escalade ESV AWD V8-6.2L Page 1944

* Vacuum hoses for splits, kinks, and improper connections

* Insufficient fuel in the tank

* Low fuel pressure-Refer to Fuel System Diagnosis (w/o FPCM) (See: Powertrain Management/Computers and Control Systems/Testing and

Inspection/Component Tests and General Diagnostics)Fuel System Diagnosis (FPCM) (See: Powertrain Management/Computers and

Control Systems/Testing and Inspection/Component Tests and General Diagnostics).

* Fuel contamination-Refer to 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))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)) for Gasoline or Fuel Composition Diagnosis

(See: Powertrain Management/Computers and Control Systems/Testing and Inspection/Component Tests and General Diagnostics) for E85.

* Malfunctioning fuel injectors-Refer to Symptoms - Engine Exhaust (See: Engine, Cooling and Exhaust/Exhaust System/Testing and

Inspection/Symptoms - Engine Exhaust).

* Missing, loose, or leaking exhaust components from the HO2S forward-Refer to Symptoms - Engine Exhaust (See: Engine, Cooling and

Exhaust/Exhaust System/Testing and Inspection/Symptoms - Engine Exhaust).

* Vacuum leaks at the intake manifold, the throttle body, and the injector O-rings

* The air induction system and the air intake ducts for leaks or for a missing air filter element

* A cracked EVAP canister

* Evaporative pipes obstructed or leaking

* The crankcase ventilation system for leaks

* The HO2S for improper installation and for electrical wires or connectors that may have contacted the exhaust system

* The HO2S signal circuit open, shorted to ground, or shorted to the low reference circuit

* Malfunctioning engine components-Refer to Symptoms - Engine Mechanical (See: Engine, Cooling and Exhaust/Engine/Testing and

Inspection/Symptom Related Diagnostic Procedures/Symptoms - Engine Mechanical).

P0172 or P0175

Allow the engine to reach operating temperature. With the engine running, observe the affected Long Term FT parameter with a scan tool. The

reading should be between -19 and 0 %.

If not within the specified range, inspect for the following:

* With the engine idling and the transmission in the Park or Neutral position, observe the manifold absolute pressure (MAP) sensor parameter.

The MAP sensor parameter should be between 19-42 kPa.

锟斤拷Refer to DTC P0106 (See: P Code Charts/P0106) if the MAP sensor parameter is not between 19-42 kPa.

* With the engine idling, observe the mass air flow (MAF) sensor parameter. The MAF sensor parameter should be within 2-6 g/s at idle.

锟斤拷Refer to DTC P0101 or P1101 (See: P Code Charts/P0101) or DTC P0102 or P0103 (See: P Code Charts/P0102) if the MAF sensor

parameter is not within 2-6 g/s at idle.

* Vacuum hoses for splits, kinks, and improper connections

* The air intake duct for being collapsed or restricted

* The air filter for being dirty or restricted

* Objects blocking the throttle body

* Excessive fuel in the crankcase due to leaking fuel injectors

* The evaporative emissions control system for improper operation

* Excessive fuel pressure-Refer to Fuel System Diagnosis (w/o FPCM) (See: Powertrain Management/Computers and Control

Systems/Testing and Inspection/Component Tests and General Diagnostics)Fuel System Diagnosis (FPCM) (See: Powertrain

Management/Computers and Control Systems/Testing and Inspection/Component Tests and General Diagnostics).

* Malfunctioning fuel injectors-Refer to Fuel System Diagnosis (w/o FPCM) (See: Powertrain Management/Computers and Control

Systems/Testing and Inspection/Component Tests and General Diagnostics)Fuel System Diagnosis (FPCM) (See: Powertrain

Management/Computers and Control Systems/Testing and Inspection/Component Tests and General Diagnostics).

* Fuel contamination-Refer to 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))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)).

* The HO2S for improper installation and for electrical wires or connectors that may have contacted the exhaust system

* The HO2S signal circuit shorted to voltage

Repair Instructions

* Air Cleaner Assembly Replacement (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine Performance Checks/Air Cleaner

Housing/Service and Repair)

* Air Cleaner Element Replacement (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine Performance Checks/Air Cleaner

Housing/Air Filter Element/Service and Repair)

* Air Cleaner Resonator Outlet Duct Replacement (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine Performance Checks/Air

Cleaner Housing/Air Cleaner Fresh Air Duct/Hose/Service and Repair/Air Cleaner Resonator Outlet Duct Replacement)

* Evaporative Emission Canister Replacement (1500 Series) (See: Powertrain Management/Emission Control Systems/Evaporative Emissions