The car engine P2603 Code contains some information about the car engine problem. Meaning of the code can explain about the car engine problem. The powertrain of the car engine may be faulty here and this code lets you know more information when you get the real meaning of the code. The real meaning of the code is the explanation and you need to use the meaning for solving the car engine properly. Do not use wrong meaning of the code for solving the car engine, you may face some more terrible problem in the car engine and you cannot fix these problems fast.