2010 Cadillac CTS Sedan AWD V6-3.6L Page 1414
Action Taken When the DTC Sets
* DTC P0449, P0498 and P0499 are Type B DTCs.
* The EVAP system will only purge during open loop.
Conditions for Clearing the DTC
DTC P0449, P0498 and P0499 are Type B DTCs.
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)
Description and Operation
Evaporative Emission Control System Description (See: Powertrain Management/Computers and Control Systems/Description and
Operation/Evaporative Emission Control System Description)
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. Command the EVAP vent solenoid valve ON and OFF with the scan tool. An audible click should be heard when changing between the
commanded states.
2. Start the engine, observe the scan tool EVAP Vent Solenoid Valve Circuit Test Status parameters. The circuit test status parameters should
display OK or Not Run.
3. Engine Idling, observe the DTC information with a scan tool. DTC P0449, P0498, or P0499 should not set.
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.
Circuit/System Testing
1. Ignition OFF, disconnect the X-420 harness connector at the rear of the fuel tank.
2. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal J and ground.
瀚慖f the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests
normal and the ignition voltage circuit fuse is open, test all components connected to the ignition voltage circuit and replace as necessary.
3. Ignition OFF, connect a test lamp between the control circuit terminal D and the ignition voltage circuit terminal J.
Note: The control circuit for the EVAP vent solenoid valve is pulled-up to voltage within the ECM, 2.6-4.6 V on the control circuit is
normal.
4. Ignition ON, use a scan tool to command the EVAP vent solenoid valve ON and OFF. The test lamp should turn ON and OFF.
瀚慖f the test lamp remains ON all the time, test the control circuit for a short to ground. If circuit/connections test normal, replace the ECM.
瀚慖f the test lamp remains OFF all the time, test the control circuit for a short to voltage or an open/high resistance. If circuit/connections
test normal, replace the ECM.
5. Test for 2.6-4.6 V between the control circuit terminal D and ground.
瀚慖f not within the specified range, replace the ECM.
