Jeep 2008 Grand Cherokee - Manual (Page 276)

Normal Starting — Gasoline Engines
The gear selector must be in the “N” (Neutral) or “P”
(Park) position before you can start the engine. Apply the
brakes before shifting into any driving gear.
NOTE: Normal starting of either a cold or a warm
engine is obtained without pumping or depressing the
accelerator pedal.
Do not press the accelerator. Use the Fob with Integrated
Key to briefly turn the ignition switch to the START
position and release it as soon as the starter engages. The
starter motor will continue to run, and it will disengage
automatically when the engine is running. If the engine
fails to start, the starter will disengage automatically in 10
seconds. If this occurs, turn the ignition switch to the
LOCK position, wait 10 to 15 seconds, then repeat the
normal starting procedure.
Extremely Cold Weather (below Ϫ 20°F or Ϫ 29°C)
To insure reliable starting at these temperatures, use of an
externally powered electric engine block heater (available
from your dealer) is recommended.
276 STARTING AND OPERATING