Hello and welcome to MedHelp's forums. We are glad you are being examined and evaluated by your doctor. Please speak with them to ask all of your questions. If you do not understand what they are saying or what a test result means, please ask them until you do understand. Take someone with you to your appointment as that may help get your questions answered. It is a doctor's responsibility to explain so that a patient can understand their health situation and next steps.
It appears you had an initial MRI that did not provide enough information for your doctor so the ERCP is requested. Here is information on the ERCP https://www.niddk.nih.gov/health-information/diagnostic-tests/endoscopic-retrograde-cholangiopancreatography. This procedure is often used to check bile ducts. It identifies things from gallstones in bile ducts, infection to tumors. Has anyone mentioned issues with your pancreas?
Your numbers that you state here for liver function are indeed very outside of normal. This can happen for a variety of reasons including a blocked bile duct which the ERCP appears to be checking for. But this warrants quick determination so it can be addressed medically. So, please work with your doctor on this important matter.