The C1138 Code is related with the car engine and if you do not know how to fix, you should not try to solve the problem. The engine code has different meanings and according to your car brand, you need to use that meaning. Manufacturer of your car has given that meaning and you should follow that meaning. The general meaning is also found for all car engine but those are not very important thing for solving the car engine. Solving the problem related with the C1138 Code is not very difficult and you do not need to expense huge money.