Three problems related to check engine light on have been reported for the 2007 Jeep Wrangler. The most recently reported issues are listed below.
Engine oil not registered on dip stick when checked. Had to add 3 quarts of oil to get to register to bottom of dip stick. Oil has been changed every 3-6k miles since took ownership in 2007. Engine light does not come on when oil is low. Problem experienced a 2nd time 5/26/2012. Checked oil and no engine oil on dipstick. Oil was changed/filled on 1/19/2012 (have records from mechanic) and only approximately 5k miles drive in that time and again 3 quarts required to even get oil to register on dip stick and again engine oil light never came on in past 5 months since last oil change. Engine appears to be "burning through" excessive amount of oil with no indication of low oil in vehicle at any time.
While driving my 07 Jeep Wrangler unlimited with 3,400 miles on it at 65 mph the electrical system momentarily cut out then all lights came on, chimes starting going, and horn was honking for a few seconds then everything went back to normal except my check engine light came on. Unfortunately it was Sunday and I couldn't have the computer read. On Monday the check engine light was off.
While driving my 2 month old Jeep Wrangler 4-door unlimited sahara on the NJ turnpike doing 65 mph the power to the call totally shut off and all engine lights came on. I could not steer or brake. After approx. 5-10 seconds, the power came back on without me doing anything. I took the car to the dealer (mcdonagh in east brunswick, NJ) two times and they told me they ran all the tests and that the vehicle is operating as designed. They did not fix the issue nor replace the car. The car is 2 months old with 5,000 miles on it.