Test Description

The numbers below refer to the step numbers on the diagnostic table.

2: A click should be heard or felt when the valve operates. Ensure that both the ON and the OFF states are commanded. Repeat the commands as necessary.
5: This step verifies that the ECM is providing ground to the EVAP vent valve.
6: This step tests if the EVAP vent valve control circuit is grounded.

DTC P0449

Step	Action	Yes	No
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1	Did you perform the Diagnostic System Check - Engine Controls?	Go to Step 2	Go to Diagnostic System Check - Engine Controls
2	Turn ON the ignition, with the engine OFF. With the scan tool, command the EVAP vent valve ON and OFF. Do you hear or feel a click from the EVAP vent valve when the valve is commanded ON and OFF?	Go to Step 3	Go to Step 4
3	Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. 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. Did the DTC fail this ignition?	Go to Step 4	Go to Intermittent Conditions
4	Disconnect the EVAP vent valve electrical connector. Probe the ignition 1 voltage circuit of the EVAP vent valve with a test lamp connected to a good ground. Does the test lamp illuminate?	Go to Step 5	Go to Step 11
5	Connect a test lamp between the control circuit of the EVAP vent valve and the ignition 1 voltage circuit of the EVAP vent valve. With a scan tool, command the EVAP vent valve ON and OFF. Does the test lamp turn ON and OFF with each command?	Go to Step 9	Go to Step 6
6	Does the test lamp remain illuminated with each command?	Go to Step 8	Go to Step 7
7	Test the control circuit of the EVAP vent solenoid for a short to voltage or for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 14	Go to Step 10
8	Test the control circuit of the EVAP vent valve for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 14	Go to Step 10
9	Inspect for poor connections at the vent valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 14	Go to Step 12
10	Inspect for poor connections at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 14	Go to Step 13
11	Repair the ignition 1 voltage circuit of the EVAP vent valve for an open or for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair?	Go to Step 14	-
12	Replace the EVAP vent valve. Refer to EVAPORATIVE EMISSION (EVAP) CANISTER VENT SOLENOID VALVE REPLACEMENT . Did you complete the replacement?	Go to Step 14	-
13	Replace the ECM. Refer to Engine Control Module (ECM) Replacement . Did you complete the replacement?	Go to Step 14	-
14	Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. 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. Did the DTC fail this ignition?	Go to Step 15	Go to Step 2
15	Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?	Go to Diagnostic Trouble Code (DTC) List	System OK