P0449
DTC P0449
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 provides an overview of each diagnostic category.
DTC Descriptors
DTC P0449
- Evaporative Emission (EVAP) Vent Solenoid Control Circuit
Diagnostic Fault Information
Circuit/System Description
Battery voltage is supplied to the evaporative emissions (EVAP) vent solenoid valve. The engine control module (ECM) grounds the EVAP vent solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. A scan tool will display the commanded state of the EVAP vent solenoid valve as Venting or Not Venting.
Conditions for Running the DTC
* The system voltage is between 11-32 V.
* DTC P0449 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 a minimum of 0.25 s.
Action Taken When the DTC Sets
DTC P0449 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P0449 is a Type B DTC.
Reference Information
Schematic Reference
Engine Controls Schematics [1][2]Electrical Diagrams
Description and Operation
Evaporative Emission Control System Description Description and Operation
Connector End View Reference
Component Connector End Views Connector End Views By Name
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, engine OFF, command the EVAP vent solenoid Not Venting - On and Venting - Off with a scan tool. You should hear the solenoid click when commanded ON and OFF.
2. Engine idling, command the EVAP vent solenoid ON and OFF with a scan tool while observing the following control circuit status parameters:
* EVAP Vent Sol Ckt Short Gnd Test Status
* EVAP Vent Sol Ckt Open Test Status
* EVAP Vent Sol Ckt Short Volts Test Status
Each parameter should display OK or Not Run.
3. Operate the vehicle within the conditions for running the DTC. 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 at the Q13 evaporative emissions vent solenoid valve.
2. Ignition OFF, verify that a test lamp illuminates between the B+ circuit terminal B or 2 and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test all components connected to the B+ circuit and replace as necessary.
3. Ignition ON, verify that a test lamp does not illuminate between the B+ circuit terminal B or 2 and the control circuit terminal A or 1.
• If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 engine control module.
4. Remove the test lamp, and install a 3 A fused jumper wire between the control circuit terminal A or 1 and the B+ circuit terminal B or 2. Command the vent solenoid ON with a scan tool. Verify the scan tool vent solenoid Ckt. Short Volts Test Status Parameter is Fault.
• If not the specified value, test the control circuit for an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
5. If all circuits test normal, test or replace the Q13 evaporative emissions vent solenoid valve.
Component Testing
1. Ignition OFF, disconnect the harness connector at the Q13 evaporative emission vent solenoid valve.
2. Test for 15-25 ohms between the control terminal A or 1 and the B+ voltage terminal B or 2.
• If not within the specified range, replace the Q13 evaporative emission vent solenoid valve.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Evaporative Emission Canister Vent Solenoid Valve Replacement (2500 Series) Service and RepairEvaporative Emission Canister Vent Solenoid Valve Replacement (2500 Series) Service and RepairEvaporative Emission Canister Vent Solenoid Valve Replacement (1500 Series) Service and Repair
* Control Module References Control Module References for ECM replacement, setup, and programming