P0449
DTC P0443 or 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 P0443
- Evaporative Emission (EVAP) Purge Solenoid Valve Control Circuit
DTC P0449
- Evaporative Emission (EVAP) Vent Solenoid Valve Control Circuit
Diagnostic Fault Information
Circuit/System Description
An ignition voltage is supplied directly to the evaporative emission (EVAP) purge solenoid valve. The engine control module (ECM) grounds the EVAP purge solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. The EVAP purge solenoid valve is pulse width modulated (PWM). A scan tool will display the amount of ON time as a percentage.
Battery voltage is supplied to the EVAP vent solenoid valve. The 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 ON (Not Venting) or OFF (Venting).
Conditions for Running the DTC
* The ignition is ON.
* The system voltage is greater than 11 V.
* DTCs P0443 and P0449 run 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 P0443 and P0449 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTC P0443 and P0449 are Type B DTCs.
Reference Information
Schematic Reference
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly - Primary
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
Note: For P0443, the audible clicking intensity will vary depending on mounting locations and interference with the fuel injectors clicking. You may also feel a change in the frequency of clicking.
P0443
1. Ignition ON, engine OFF, you should hear or feel a clicking sound when the EVAP purge solenoid valve is commanded to 50 % with a scan tool. The clicking sound or feel should stop when the EVAP purge solenoid valve is commanded to 0 %. The rate at which the valve cycles should increase when the commanded state is increased, and decrease when the commanded state is decreased.
2. 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.
P0449
1. Ignition ON, engine OFF, command the EVAP vent solenoid ON (Not Venting) and OFF (Venting) with a scan tool. Listen or feel for a click when the valve operates.
2. Verify that both the ON (Not Venting) and the OFF (Venting) states are commanded with a scan tool while observing their parameter status.
* EVAP Vent Solenoid Valve Control Circuit High Voltage Test Status
* EVAP Vent Solenoid Valve Control Circuit Low Voltage Test Status
* EVAP Vent Solenoid Valve Control Circuit Open 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,
* Q12 evaporative emission purge solenoid valve for P0443
* Q13 evaporative emission vent solenoid valve for P0449
2. Ignition ON, verify that a test lamp illuminates between the voltage supply circuit,
* Terminal 1 or A and ground for the purge solenoid valve
* Terminal 2 or B or A and ground for the vent solenoid valve
• If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the voltage supply circuit fuse is open, test all components connected to the voltage supply circuit and replace as necessary.
3. Connect a test lamp between the voltage supply circuit and the control circuit.
4. With a scan tool command the,
* EVAP purge solenoid valve to 50 %
* EVAP vent solenoid valve ON (Not Venting) and OFF (Venting)
The test lamp should respond to the command
• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 engine control module.
• If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
5. If all circuits test normal, replace the appropriate 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, setup, and programming.