Due to the diagnosis of the car engine, the B1668 Code has come up. The dictionary meaning of the code is B for Body Code Problem is antilock brake system, electronic suspension and steering systems. 1 for MFG – Manufacturer Specific. 6 for Vehicle Speed Control and Idle Control System. 6 for Control Module Throttle Actuator Position Performance and 8 for PCM Stack Overrun. The code has started with the B and the problem of the engine is related with the body of the engine. It is easy to solve the problem. Mainly connection of the engine is the main problem what is easy to fix.