P0449
DTC P0449 (LUW)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provide an overview of each diagnostic category.
DTC Descriptor
DTC P0449
- Evaporative Emission (EVAP) Vent Solenoid Valve Control Circuit
Circuit/System Description
The evaporative emission (EVAP) vent solenoid valve is used for EVAP system diagnostics. The EVAP vent solenoid valve is a normally open valve. Battery voltage is supplied directly to the EVAP vent solenoid valve. The engine control module (ECM) controls the solenoid by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.
Conditions for Running the DTC
* The ignition is ON.
* The ignition voltage is between 11-32 V.
* The run/crank voltage goes to 0.0 V after ignition OFF.
* The EVAP vent solenoid valve is enabled.
* The DTC runs continuously when the above conditions are met.
Conditions for Setting the DTC
The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for greater than 5 s.
Action Taken When the DTC Sets
DTC P0449 is a Type B DTC.
Conditions for Clearing the DTC
DTC P0449 is a Type B DTC.
Reference Information
Schematic Reference
Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly
Description and Operation
Evaporative Emission Control System Description Description and Operation
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON, command the EVAP Vent Solenoid ON and OFF with a scan tool. You should hear the solenoid click when commanded ON and OFF.
2. Verify the control circuit status parameters listed below do not display Malfunction:
* EVAP Vent Sol Short Ground Test Status
* EVAP Vent Sol Open Test Status
* EVAP Vent Sol Short Volts Test Status
3. Verify the control circuit status parameters listed below do not display malfunction while commanding the EVAP Vent Solenoid Valve to Not Venting:
* EVAP Vent Sol Short Ground Test Status
* EVAP Vent Sol Open Test Status
* EVAP Vent Sol Short Volts Test Status
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 harness connector X350 Body Harness & Fuel Tank Harness.
2. Ignition ON, verify a test lamp illuminates between the B+ voltage circuit terminal E female and ground.
• If the test lamp does not illuminate, test the B+ voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ voltage circuit fuse is open, test all components connected to the B+ voltage circuit and replace as necessary.
3. Test for 2.5-3.5 V between the control circuit terminal D female and ground.
• If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the K20 Engine Control Module.
• If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
4. Command the EVAP Vent Solenoid Valve between Not Venting and Venting with a scan tool. The DMM should transition from 2.5-3.5 V when OFF to less than 0.1 V when commanded ON.
• If the circuit voltage does not correspond to the specified values, replace the K20 Engine Control Module.
5. Test for 15-25 ohms between the control circuit terminal D male and the B+ voltage circuit terminal E male.
• If greater than the specified range, test the control circuit or the B+ voltage circuit for an open/high resistance. If the circuit tests normal, replace the Q13 Evaporative Emission Vent Solenoid Valve.
6. If all circuits test normal, replace the Q13 Evaporative Emission Vent Solenoid Valve.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
Control Module References Control Module References for ECM replacement, programming, and setup