This bulletin involves DTC P0456 on 2007-2008 Ford E-150, E-250, E-350 and Expedition F-150; and 2007-2008 Lincoln Mark LT and Navigator.
ISSUE: Some of these vehicles may exhibit a MIL-on with DTC P0456 (very small evaporative system leak….0.020 in. in diameter).
Perform the following diagnostic steps when this DTC is found in memory. The procedure requires validation of the evaporative system leak size before attempts are made to locate and repair the leak. Use of a Vacutec leak machine or equivalent machine is required for this procedure.
NOTE: Currently the IDS EVAP leak measurement tool is not capable of measuring leaks less than 0.035 in. in diameter. IDS cannot be used to measure leak size or validate repair for DTC P0456.
Many EVAP leaks are caused by a loose or damaged fuel cap. If the fuel cap is suspected during a visual inspection, do not disturb the cap until the leak verification pressure test is completed.
Before attempting to locate or repair leaks, first verify leak size using a Vacutec machine.
Prepare the vehicle for hook-up to the Rotunda Vacutec or equivalent machine.
When using the Vacutec machine, the fuel level in the tank must be greater than 15% and less than 85%.
Connect the Vacutec machine power cables to the vehicle battery. Check to see that the Vacutec power indicator lamp is on, indicating good battery contact. Disconnect the fuel vapor to intake manifold line at the electrical vapor management valve (eVMV) and cap the line. Connect a 5/16-inch ID flexible vinyl clear hose with a wall thickness of 1/16-inch to the eVMV. This will be used to connect the Vacutec.
Run the Vacutec machine leak verification pressure test. Position the control lever located on the Vacutec machine to “meter.” Calibrate the Vacutec machine flow meter using the 0.020 (DTC P0456) standard as follows: