Mercury Mountaineer 2009 Owner's Manual page 747

Roadside Emergencies
3. Remove the jumper cable from the positive (+) terminal of the booster
vehicle's battery.
4. Remove the jumper cable from the positive (+) terminal of the
disabled vehicle's battery.
After the disabled vehicle has been started and the jumper cables
removed, allow it to idle for several minutes so the engine computer can
relearn its idle conditions.
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2009 Mountaineer (mnt)
Owners Guide, 1st Printing
USA (fus)