2010 Cadillac CTS Sedan AWD V6-3.6L Page 1462
The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. If the ECM
detects the control circuit voltage is within a predetermined range when the circuit is commanded OFF, this DTC sets.
Conditions for Running the DTC
* The engine speed is greater than 80 RPM.
* The ignition voltage is between 10-18 volts.
* The ECM has commanded the EVAP canister vent valve ON and OFF at least once during the ignition cycle.
* The DTCs runs continuously once the above conditions are met.
Conditions for Setting the DTC
P0449
The ECM detects the voltage on the EVAP canister vent valve control circuit is between 2.6-4.6 volts when the driver is commanded OFF. The
condition exists for less than 4 seconds or for a cumulative of 30 seconds.
P0498
The ECM detects the voltage on the EVAP canister vent valve control circuit is less than 2.6 volts when the driver is commanded OFF. The
condition is present for greater than 4 seconds or for a cumulative of 30 seconds.
P0499
The ECM detects the voltage on the EVAP canister vent valve control circuit is greater than 4.6 volts when the driver is commanded ON. The
condition is present for greater than 4 seconds or for a cumulative of 30 seconds.
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.
