2010 Cadillac Truck SRX FWD V6-3.0L Page 2004
Action Taken When the DTC Sets
DTCs P2178 and P2188 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P2178 and P2188 are Type B DTCs.
Diagnostic Aids
* A fuel system delivery condition causes this DTC to set. Thoroughly inspect all items that cause a rich 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)).
* Review the Freeze Frame/Failure Records with a scan tool.
Reference Information
Schematic Reference
Engine Controls Schematics (LAU) (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/Connector End Views By Name)
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 P2178 or P2188 should not be set.
瀚慖f there are other DTCs set besides DTC P2178 or P2188, 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 BARO 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/Altitude Versus
Barometric Pressure).
瀚慖f the BARO pressure is not within the range specified for your altitude, refer to DTC P2227, P2228, or P2229 (LAU) ( See: P Code
Charts/P2227).
3. Engine at normal operating temperature, observe the Average Total Fuel Trim parameter with a scan tool. The Average Total Fuel Trim
should be between -22 to +23 percent.
瀚慖f not within the specified range, inspect for the following conditions:
* A mass air flow sensor signal that is skewed. If the Short Term Fuel Trim parameter changes greater than 20 percent when the MAF
sensor is disconnected, refer to DTC P0101 (LAU) (See: P Code Charts/P0101)DTC P0101 (LF1) (See: P Code Charts/P0101).
* A collapsed air intake duct
* A restricted air filter element-Refer to Air Cleaner Element Replacement (LF1) (See: Engine, Cooling and Exhaust/Engine/Tune-up and
