Ford 2011 Econoline Owner's Manual page 267

Auxiliary battery (if equipped)
Your vehicle may be equipped with a frame-mounted auxiliary battery
located on the passenger side frame rail, behind the front passenger
door. This auxiliary battery is connected to the auxiliary battery relay, so
it is not used to start the vehicle.
Because your vehicle's engine is electronically controlled by a computer,
some control conditions are maintained by power from the battery. When
the battery is disconnected or a new battery is installed, the engine must
relearn its idle and fuel trim strategy for optimum driveability and
performance. Flexible fuel vehicles (FFV) must also relearn the ethanol
content of the fuel for optimum driveability and performance. To begin
this process:
1. With the vehicle at a complete stop, set the parking brake.
2. Put the gearshift in P (Park), turn off all accessories and start the
engine.
3. Run the engine until it reaches normal operating temperature.
4. Allow the engine to idle for at least one minute.
5. Turn the A/C on and allow the engine to idle for at least one minute.
6. Release the parking brake. With your foot on the brake pedal and with
the A/C on, put the vehicle in D (Drive) and allow the engine to idle for
at least one minute.
7. Drive the vehicle to complete the relearning process.
• The vehicle may need to be driven 10 miles (16 km) or more to
relearn the idle and fuel trim strategy along with the ethanol content
for flexible fuel vehicles.
• If you do not allow the engine to relearn its idle trim, the idle
quality of your vehicle may be adversely affected until the idle
trim is eventually relearned.
• For flexible fuel vehicles, if you are operating on E85, you may
experience poor starts or an inability to start the engine and
driveability problems until the fuel trim and ethanol content have been
relearned.
2011 Econoline (eco)
Owners Guide, 3rd Printing
USA (fus)
I n f o r ma t i o n P r o v i d e d b y :
Maintenance and Specifications
267