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 greater than 11 V.
* The DTC run once an ignition cycle 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 seconds.

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 (LUW) [1][2]Electrical Diagrams
Connector End View Reference

Component Connector End Views Sunshade - Left (D6I)
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. 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 Short Ground Test Status
* EVAP Vent Sol Open Test Status
* EVAP Vent Sol Short Volts Test Status

• Each parameter should display OK or Not Run.

3. 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 at the Q13 Evaporative Emission Vent Solenoid Valve.
2. Ignition ON, verify a test lamp illuminates between the B+ voltage circuit terminal B 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 A 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 ON and OFF 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. If all circuits test normal, test or replace the Q13 Evaporative Emission Vent Solenoid Valve.

Component Testing

Static
1. Ignition OFF, disconnect the harness connector of the Q13 Evaporative Emission Vent Solenoid Valve.
2. Test for 15-25 ohm between the control terminal A and the B+ voltage terminal B.

• If not within the specified range, replace the Q13 Evaporative Emission Vent Solenoid Valve.

3. Test for infinite resistance between each terminal and the Q13 Evaporative Emission Vent Solenoid Valve housing.

• If not the specified value, replace the Q13 Evaporative Emission Vent Solenoid Valve.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

Control Module References Control Module References for ECM replacement, programming, and setup