The B1242 Code is an error diagnosis code of engine. It is important to read the manual and know the model and manufacture to solve the problem. Reading the manual of the engine and car is very important. Due to the model and manufacture, the meaning of the B1242 Code is changed. The engine system, in combination with the engine control module or powertrain control module, triggers the B1242 code solenoid valve to control oil compression to the engine mechanism that is setup in the valve system to switch valve timing between high and low. If the engine solenoid valve has a short circuit or open, a DTC is stored.