The passive antitheft system, or PATS, for your Ford Expedition is installed on every vehicle at the factory. The system is designed to prevent the engine from starting if the correct key is not used. When the antitheft system in a Ford Expedition has been activated you will not be able to start the engine until the system has been turned off. You can turn off the antitheft system in a Ford Expedition by starting the vehicle with your existing factory key.
Open the driver side door and see if there is a red light flashing on the dashboard above the steering wheel. A flashing red light will indicate that the passive antitheft system has been activated.
Verify that you have the correct key for the vehicle. The original equipment key is needed to start the engine. Examine the key and see if the end is covered with moulded rubber. If you have a copy of a key or a key that is damaged the vehicle will not start.
Get in the vehicle and insert the original or factory key into the ignition and turn it to start the vehicle. If the vehicle starts the antitheft system has been turned off.
Take off any metallic or electronic devices from your key chain. Some metallic objects or electronic devices can interfere with the antitheft system and cause the vehicle not to start. Insert the key into the ignition and turn it to see if the vehicle will now start.
Take off any additional car keys if more than one is on your key chain. More than one of the same type of key, will cause interference and prevent the car from starting. Insert the key into the ignition and turn it to see if the vehicle will now start.
The moulded rubber on the factory key contains that chip that stores the information that is used by the PATS transponder to recognise the key. If you no longer have your keys because they have been lost or stolen, you will have to take the Expedition to a dealership for new keys to be programmed for your vehicle.
You cannot permanently disable the passive antitheft system on your Ford Expedition.