Ok I had this Jeep I’ve done everything with it been going through this for 3 months now but I think I finally found the codes but i dnt know what they mean or even how to go about it the codes are 12 27 54 55 can someone hel me alil
This good answer has a list of all Jeep OBDI codes, pulling out the relevant ones we have:
12 memory to controller has been cleared within 50-100 engine starts 27 injector control circuit does not respond to control signal 54 camshaft reference circuit not detected 55 end of message
12 and 55 are not errors, 27 and 54 are, so concentrate on them.
This answer explains fault 27, and has detailed instructions on how to check. Summed up you have a disconnected injector, a broken injector or a problem in the injector control wiring.
Error code 54 has to do with a sensor in the distributor, either failed or disconnected:
54 means the camshaft sensor's signal is missing. The camshaft sensor is inside the distributor with its connector cable leading out from underneath the cap. It's a little flat ribbon cable.
This forum post has more details, basically check to see if it is connected properly, placement varies by engine type.
If you've been doing some work make sure your cabling is connected and in the right places. Ensure your injectors are plugged in the right order.