2010 Cadillac Truck SRX FWD V6-3.0L Page 1239

2010 Cadillac Truck SRX FWD V6-3.0L Page 1239

DTCs P0171, P0172, P0174, and P0175 are Type B DTCs.

Diagnostic Aids

* Allow the engine to reach operating temperature. With the engine running, observe the HO2S parameter with a scan tool. The HO2S value

should vary from approximately 40 mV to approximately 900 mV, and respond to fueling changes.

* The normal Short Term FT and Long Term FT parameters should be between +10 and -10 % with 0 % the optimum, with the engine running

at operating temperature.

* An HO2S will not cause this DTC to set without the occurrence of the circuit related HO2S DTCs. Do not replace an HO2S to address this

DTC.

* A fuel system delivery condition causes this DTC to set. Thoroughly inspect all items that cause a rich or a lean condition. 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)).

* 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

Electrical Information Reference

* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit

Testing/Circuit Testing)

* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic

Procedures/Connector Repairs/Connector Repairs)

* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General

Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)

* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/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 P0171, P0172, P0174, or P0175 should not be set.

2. Engine running, observe the DTC information with a scan tool. Verify there are no HO2S DTCs set.

瀚慖f any HO2S DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code

Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle).

3. Ignition ON, observe the manifold absolute pressure (MAP) sensor parameter. The MAP sensor pressure should be within the range specified

for your altitude. Refer to Altitude Versus Barometric Pressure (See: Powertrain Management/Computers and Control

Systems/Specifications/Altitude Versus Barometric Pressure).

瀚慖f not the specified range, refer to DTC P0106 (LF1) (See: P Code Charts/P0106).

Note: EVAP purge enablement may cause the FT to be momentarily outside the normal range.

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

The value should be between -20 % and +20 %.

瀚慖f not the specified range, inspect for the following:

P0171 or P0174

* 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 (LAU) (See: P Code Charts/P0101)DTC P0101 (LF1) (See: P Code Charts/P0101).

* Fuel contamination-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