That is a fan relay error. Recommend replacing the relay, these jeeps are notorious for burning them up.
P0302 is Misfire Detected in Cylinder 2. If it is the 4.0 inline 6, this will be the second cylinder from the front. I do not know off the top of my head which is cylinder number 2 for the 4.7 V8.
Engine speed sensor circuit malfuntion
12 is no spark to the coil (normal when off) and 55 is end of error codes depending on the year
Trouble code P0601 means: Internal Control Module Memory Check Sum Error
The "bus" is the communication system for the computers on the vehicle. Any computer, wire, or connection can cause that problem.
6???? the code should be like this ie: P0301. Please reask question with the code number..
You can cause the "CHECK ENGINE" light to blink the error codes.Without starting the engine, turn the ignition key on, off, on, off, and back to on.The "CHECK ENGINE" light will flash the first digit, pause and then flash the second digit of any stored error.Example:one flash and pause and eight flashes = number 18 error code.You can also try this inclusive web page that can itemize most error codes for you. To read them from the car's computer you need an ODBII compliant reader , either computer program or utility tool from most car part retailers.. ie about $200answer1995 grand Cherokees are not ob 2 compliant listen to the first bit of information because it is correct. When you are turning the key switch back and forth 2 or three times between acc and off. http://www.wjjeeps.com/faultcodes.htm
Go to www.banzai-racing.com , it will tell you how to get the error codes and what they are.
55 code is not an error code, it signals end of codes. If no other codes preceded it, you have no error codes.
Visit Gamefaqs.com and go to the cheats/codes section for MMBN3. You'll get error codes, numberman codes, ex codes, SHRINK codes (those are helpful) and more.
Code 13 is no vehicle speed sensor signal. Check/replace the speed sensor on the tailshaft of the transfer case.