The B1691 Code has a meaning for each car engine and if you want to solve the problem, you need to use several machines and information. Vehicle to vehicle, the meaning of the code changes. You should get the model number and manufacture name of the car for solving the problem. The dictionary meaning of the B1691 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. 9 for Crankshaft Position Sensor Circuit Performance and 0 for Transmission Engaged at High Throttle Angle.