I was stuck in snow and while rocking the vehicle back and forth the check engine light came on, anyone know why this would happen? maybe had something to do with shifting tranny, between F and R to get vehicle rocking?

 

I've experience the check engine light coming on when the tranny doesnt automatically downshift after a few times (probably 5 or more times)
but I havn't had it happen while rocking it... dont know if it will go past 1st gear either... since the mileage doesn't go up, unless you were in 4wd... and it calculated the wheel spin to shift up... then you put it to reverse without giving it enough time to downshift on its own...

id take it somewere plug it to an OBD2 and see what the trouble code is, (some places will give you a free read, but if its a generic reader its sometimes not detailed information, the codes can be found on the internet ofcourse...)

if it seems to be running right, id just pull the negative on the battery, and see if it comes back on...

 

i have the 05 GC HEMI its got quadra drive II all time 4wd and my model has a built in code reader on EVIC i get codes p0573 and p0700

 

Well from what i know on my WJ, P is a powertrain troublecode, those codes display the following for my jeep, I imagine their the same... you never know

P0573
"Cruise Control/Brake Switch A Circuit High"

P0700
"This code indicates that the EATX (Transmission controller) has an active fault and has illuminated the MIL via a BUS message. The specific fault must be acquired from the EATX via a DRBIII tool. (Input or Output Speed Sensor failures often cause this code and are a common failure part on WJ Grand Cherokees)."

I've been looking on WKJeeps.com to see if i can find the codes for it, but cant find them, so i used what the WJ says...

 

Muddin24/7,
If your Jeep is still operating properly other than the light on, disconnect the battery for about 10-15 minutes and let the PCM power down. When you reconnect see if it re-lights after a few starts. If not it was most likely just a fault code thrown from a combination of brake, gas, F/R that the computer didn't react to fast enough. After about 40 normal restarts if the problem hasn't happened again the computer will erase the code.

Dan